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Hot rolling and cold rolling

Treatment Method For Sanitary Pipe Fittings

Advantages and disadvantage of Hot rolling and cold rolling of stainless steel

Hot rolling and cold rolling are the two most commonly used processes for forming steel or steel plates. They are also the most basic steel processing methods.

Hot rolling and cold rolling

This two treatments can have a great impact on the structure and performance of stainless steel. The rolling stress of steel is based on hot rolling. Cold rolling is mainly only used for the production of small sections and thin plates.


I. Hot rolled for sanitary pipe fittings

Advantage:

It can destroy the casting structure of the steel ingot, refine the grain of the steel, and eliminate the defects of the microstructure, so that the steel structure is dense and the mechanical properties are improved. This improvement is manifested in the upward direction of the rolling, so that the steel is no longer isotropic to a certain extent; the bubbles, cracks and looseness formed during casting can also be welded under the action of high temperature and pressure.

Disadvantages:

 

  • 1. After hot rolling, the non-metallic mixture (tension is sulfide and oxide, and silicate) inside the steel is pressed into thin sheets, and signs of delamination (interlayer) appear. Delamination greatly deteriorates the tensile properties of the steel along the thickness direction, and interlayer tearing may occur when the weld is tightened. The local strain induced by weld shrinkage often reaches several times the yield point strain, which is much larger than the strain caused by the load.
  • 2. The dross stress caused by uneven cooling. The dross stress is the internal self-balanced stress without external force. Hot-rolled steel sections of various cross-sections have such dross stress. The larger the section size of ordinary steel, the greater the dross stress. Although the dross stress is self-balanced, it still has a positive effect on the performance of steel components under external forces. Such as deformation, stability, resistance to fatigue, etc., may have unlucky effects.

II, Cold rolling for sanitary pipe fitting

It refers to the steel plate or steel strip processed into various types of steel by cold drawing, cold bending, and cold drawing at room temperature.

Advantages:

Unlike Hot rolling cold rolling has fast forming speed, high output, and without damaging the coating, it can be made into a variety of cross-sectional forms to meet the needs of utilization conditions; cold rolling can cause large plastic deformations in the steel, thereby improving the steel Yield point.

Disadvantages:

 

  • 1. Although there is no thermal plastic compression during the forming process, slag stress still exists in the section, which affects the characteristics of the steel group and local buckling.
  • 2. The style of cold-rolled steel is usually an open section, which makes the free rotation stiffness of the section low. It is easy to rotate when being bent, and bend torsional buckling when being pressed, and its torsion resistance is poor.
  • 3. The wall thickness of cold-rolled steel is small, and the corners where the plates are joined are not thickened, and the load is weak.
Sanitary stainless steel clamp

How Does Sanitary Clamp Works On The Pipeline

Classification And Technical Use Of Clamps

First of all, let’s understand what a sanitary clamp is? Although this term doesn’t work on pipes, it has a great effect; so far, many people still don’t know what the clamp looks like. There are many sanitary clamps includes heavy duty single pin clamp, double pins clamp and safety clamps etc; here sanitary pipe fittings supplier – wellgreen will focus on how does clamp works on pipelines.

Sanitary stainless steel clamp

Sanitary stainless steel clamp

Sanitary clamps聽are also called聽hygienic clamps.聽Sanitary clamps聽are divided into hose clamps and hoops. What are hose clamps and hoops we will continue to talk about below; the main purpose of sanitary clamps is also named according to its name. The word sanitary is meant to be clean, clean and hygienic. Its use value is also very high, because sanitary clamps are basically used in food pipelines and medical pipelines.

Forming and technical parameters of sanitary on how does clamp works:

1. Sanitary clamps are formed by casting stainless steel and stamping stainless steel plates; the so-called casting means that stainless steel is melted into a liquid at a high temperature of 1550 degrees Celsius, and then poured into a refined silicon melt mold to slowly cool and form. This is only the blank molding of the clamp, not the finished product; there are also components that have undergone surface treatment (vibration) and perforation, rivet retention, ingot nut and other components. Vibration refers to the use of vibration technology to polish and must be hygienic Clean standard; this is a perfect quality product.

2. The application field of sanitary clamps is more common in food and medical pipelines. As mentioned above, I will explain in detail here; why the surface should be polished, because the docking equipment of food and medical pipelines must basically meet the national sanitary standards , Even its finish must have a certain standard. If the user has higher requirements on the product, the stainless steel and high nickel materials SUS304 and SUS316L are basically used; this kind of sanitary clamp is also used in chemical equipment and water treatment equipment.

3. The stainless steel stamping clamp is relatively simple, the manufacturing process is simpler; it is stamped and formed from a stainless steel plate, and then matched with the relevant components; the surface of the product can be polished or whitened according to the user.

4. The nominal pressure of sanitary clamps can be 0~4.0mpa, divided into low pressure clamps, normal pressure clamps and high pressure clamps.

5. Sanitary clamps currently available in the market have diameters ranging from DN15 to DN630; larger ones need to be customized.

The above is just a brief introduction to the molding and technical parameters of several clamps about how does clamp works.

polished stainless steel tubing

There Is Still Demand For Rush Work Before Winter For Sanitary Stainless Steel Pipes

There Is Still Demand For Rush Work Before Winter For Sanitary Stainless Steel Pipes

Since August this year, the equatorial Central and Eastern Pacific has entered the La Ni帽a state. According to China’s National Climate Center, the state of La Ni帽a will continue to be maintained in the fall, and it is expected to reach its peak in this winter, that is, a weak to moderate La Ni帽a event will occur this winter. Since 2000, there have been 5 La Ni帽a events. In terms of the status of the 5 La Ni帽a events, the average temperature in parts of eastern Inner Mongolia, Northeast China, and North China in winter is 1-2掳C lower than normal in the same period, and in some areas it is 2掳C lower. According to the data of previous years, the impact on China’s winter climate may be more obvious, which is likely to cause China’s winter climate to be colder, which is not conducive to construction in the north, especially the Xiongan area, and is bad for the demand for sanitary stainless steel tubings and sanitary stainless steel pipes.

polished stainless steel tubing

Sanitary stainless steel pipe market: strong reality vs weak expectation

[Today, Tangshan’s environmental protection control is strengthened again] Since 18:00 on October 23, 2020, the city has launched a Class II emergency response to heavy pollution weather. Increasing the proportion of sintering machine production limit for blast furnaces, converters, limes, pellets in the iron and steel industry; the coke oven load of Class B enterprises in the coking industry is reduced to less than 80% of the designed production load, and the coking time shall not be less than 28 hours based on the delayed coking time; The coke oven load of C-level enterprises is reduced to less than 65% of the design production load, and the coking time shall not be less than 36 hours based on the delayed coking time. This morning, the billet rose 10 yuan to 3440 yuan/ton, and the rolling mill is facing production suspension again, and the market expects a strong atmosphere.
[Steel pipes] Tangshan pipe prices have risen steadily, and raw materials have continued to rise slightly. The sanitary stainless steel pipe market has followed the rising sentiment, and merchants are actively shipping.

Significant recovery in demand for building materials

This week the demand for building materials has recovered significantly, especially in East China, which is close to the level after the Spring Festival, and the pressure on North Materials is relatively high due to weather factors. The apparent demand for threaded threads was 4,164,200 tons, a decrease of 271,200 tons from last week, but it was still at a high level during the year. More than 410 watch demand also indicated that it was in the peak season, but the market is not optimistic about the future. Looking at it now, the peak season time is limited. And after that, demand weakened from the previous month, leaving time for high inventories. In the case of high inventory and high supply, traders are cautious and focus on digesting their own inventory, thereby suppressing spot prices.

The supply of sanitary stainless steel pipes remains high

Today, the Bureau of Statistics released the latest production data for October. In mid-October, the average daily crude steel output of key steel enterprises increased by 0.14% month-on-month. On the one hand, it shows that the supply remains high, on the other hand, it also shows that the current terminal demand is not bad. Compared with the peak season demand, the pressure of high supply in the early period has eased, but it still maintains a relatively medium-to-high level. From the perspective of steel plant maintenance plans, steel companies have no obvious long-term shutdown maintenance plans in October. Sanitary stainless steel pipe market Also, the supply relief space has not yet seen much performance, and the pressure of high production under high inventory continues to exist.

Summary: Entering the end of October, the terminal demand of sanitary stainless steel pipe market is slowing down due to the interference of weather factors. This week, the decline of social warehouse factories and warehouses has slowed down. The market mentality is cautious. The price of sanitary stainless steel pipes continues to rise. The demand is still there, and the market volume has declined, but it is still at a relatively high level. Considering the settlement period at the end of next week, the market is expected to be volatile and apparent consumption is still relatively high.

Annealing Sanitary Seamless Pipes

What Is The Purpose Of Annealing Sanitary Seamless Pipes

Why does 316 sanitary seamless pipes needs to be annealed

With the wide application of stainless steel in all walks of life, especially in food processing, food machinery, dairy products and other industries, as the market鈥檚 quality requirements for stainless steel pipes are becoming more and more demanding, the product鈥檚 smoothness, outer diameter and wall thickness deviation far from reaching the requirements, as a sanitary pipe fittings supplier, wellgreen always supply annealed sanitary seamless pipes.

Annealing Sanitary Seamless Pipes

Simply put, there are two types of annealing: A, ordinary annealing, B, bright online annealing

The purpose of annealing 316 seamless stainless steel pipe includes the following three aspects:

  • (1) Reduce hardness and improve machinability;
  • (2) Eliminate residual stress, stabilize size, reduce deformation and crack tendency;
  • (3) Refine the crystal grains, adjust the organization, and eliminate organizational defects.

In production, the annealing process is widely used.

Depending on the purpose of annealing the workpieces, there are many annealing process specifications. Commonly used are complete annealing, spheroidizing annealing, and stress relief annealing.

  • 1. Complete annealing. Used for refining the coarse superheated structure of medium and low carbon steels with poor mechanical properties after casting, forging and welding.
  • 2. Spheroidizing annealing. Used to reduce the high hardness of tool steel and bearing steel after forging.
  • 3. Isothermal annealing. It is used to reduce the high hardness of some alloy structural steels with high nickel and chromium content for cutting.
  • 4. Recrystallization annealing. It is used to eliminate the hardening of metal wires and plates during cold drawing and cold rolling (increased hardness and decreased plasticity).
  • 5. Graphitization annealing. Used to make cast iron with a large amount of cementite into malleable cast iron with good plasticity.
  • 6. Diffusion annealing. It is used to homogenize the chemical composition of alloy castings and improve their performance.
  • 7. Stress relief annealing. Used to eliminate internal requirements for steel castings and welded parts.
polished stainless steel tubing

The Macro Environment Of China’s Sanitary Stainless Steel Pipe Market

The Macro Environment Of China’s Sanitary Stainless Steel Pipe Market

Today, the price of sanitary stainless steel pipe has increased since last weekend, and it has increased significantly today.

polished stainless steel tubing

stainless steel sanitary tubing

Raw materials rose more than finished materials, iron ore rose by more than 4%, approaching the 860 yuan mark, and coke rose by more than 3%, which was the main reason.

However, iron ore, which took the lead in the late trading, surpassed and declined, the rate of increase narrowed, capital was lost, and iron ore and coke lost more than 1.1 billion yuan in blood loss.

Driven by the production restriction in Tangshan and the futures market, confidence in the sanitary stainless steel pipe market has been boosted. The transaction situation is more favorable than last week, and the overall trading atmosphere is more active.

One stone caused a wave of waves, and the long-lost production restriction hit again. From its own point of view, the impact on the time and scope of the production restriction is not great, but because this is an enhanced version of the previous implementation that is not in place, it has caused The market for sanitary stainless steel pipes has increased expectations for future fall and winter production restrictions.

However, the current production restriction is more like a tipping point, and saniatry pipe fittings supplier pays more attention to the real implementation strength and degree of landing in the later period.

The macro environment of the overall sanitary stainless steel pipe market cannot be ignored:

Last week, the central bank clearly adhered to the monetary policy of “three constants” and continued to deepen the LPR reform. The interest rate of corporate loans will fall further, giving the market a reassurance.

Immediately entering the delivery month, the sanitary stainless steel pipe market will be more volatile.

But we must also pay attention to risks. Today, the northbound capital, which is the weather vane of the stock market, has seen a large outflow. As of the close, the net outflow was as high as 8 billion yuan. This data also hit a new high since July 24.

In the short term, the market for sanitary stainless steel pipes still has an upward opportunity.

polished stainless steel tubing

Can The Demand For Sanitary Seamless Pipes Rise To The Next Level From August

Can the price of sanitary seamless pipe continue to rise in the later stage?

Nearly halfway through August, the off-season demand for traditional seasonal sanitary seamless pipe has entered a countdown, and the peak demand season is coming. Under the influence of the rush period after the epidemic, the price of sanitary seamless pipes in July this year showed a trend of “not low in the off-season”. With the arrival of the peak demand season, can the demand for sanitary seamless pipes rise to the next level, and can prices continue to rise in the future?

polished stainless steel tubing

Since the end of May, southern China has entered the rainy season. The continuous rains have caused many provinces and cities such as Anhui, Zhejiang, Jiangxi, Hubei, and Hunan to experience unprecedented floods in many years. Under the influence of heavy rains, traffic was blocked, construction of open-air buildings was severely disrupted, and some projects were forced to suspend construction, resulting in a significant drop in the demand for sanitary seamless pipes. However, this phenomenon has now been alleviated, and the rainy weather in the south has gradually weakened, driving the demand for sanitary seamless pipes to continue to rise.

The recent improvement in demand is also reflected in the social inventory of sanitary seamless pipes. It is worth noting that this is also the first time that social inventories have fallen after six consecutive weeks of growth. It can be seen that the growth rate of the social inventory of sanitary seamless pipes this year has slowed down compared with the same period last year, which indirectly reflects that this year’s demand is better than last year.

In addition, production has repeatedly set new highs, and slowed down in early August, with a slight fall. With the decline in output, it has played a certain role in alleviating the relationship between supply and demand in the sanitary seamless pipe market.

Recently, the price of “iron ore”, which has been pushed to the forefront, has continuously hit new highs. The rising prices of steel-making raw materials have provided strong support to the price of sanitary seamless pipes.

For the later trend of the sanitary tubings market, in August, after entering the peak demand season, the demand for construction steel will gradually improve, and the supply-demand relationship will be improved.

Ni(NO3)2路6H2O

Definition: Nickel, Ferronickel, Nickel Pig Iron, Nickel-based Alloys

What are Nickel? Ferronickel? Nickel Pig Iron? Nickel-based Alloys?

Through this article, sanitaryvalvefittings.com, the sanitary pipe fittings supplier will introduce to you what nickel, nickel iron, nickel pig iron and nickel-based alloys are, their characteristics, uses, etc.

Ni(NO3)2路6H2O

Ni(NO3)2路6H2O

Nickel

Nickel is a transition metal element, element symbol Ni, located in group VIII of the fourth period, atomic number 28. Nickel is mainly used in the fields of steel, nickel based alloys, electroplating and batteries, and is widely used in various military manufacturing industries such as aircraft and radar, civil machinery manufacturing and electroplating industries. Nickel is one of the important raw materials for stainless steel. Nickel consumption in China’s stainless steel industry accounts for more than 80% of primary nickel consumption and more than 2/3 globally.

Ferronickel

An alloy of iron and nickel with a nickel content of 15% or more (mass fraction) and less than 80% (mass fraction) obtained from oxide ores or other nickel-containing materials. According to the national standard GB/T25049-2010, ferronickel can be divided into five categories: low-carbon ferronickel, low-carbon low-phosphorus ferronickel, medium-carbon ferronickel, medium-carbon low-phosphorus ferronickel, and high-carbon ferronickel.

Nickel pig iron

Nickel pig iron

Nickel Pig Iron

The nickel content of nickel pig iron is less than 15%. Generally, according to the nickel content of nickel pig iron, it can be divided into high-grade nickel pig iron (10% and above), medium-grade nickel pig iron (4–9%), and low-grade nickel pig iron. Nickel pig iron is smelted mainly in submerged arc furnaces and blast furnaces. Generally, submerged arc furnaces produce high-grade nickel pig iron, and blast furnaces produce low-grade nickel pig iron. Nickel pig iron is an important source of nickel raw material for stainless steel.

Nickel-based Alloy

Nickel-based alloy refers to an alloy based on nickel (with nickel content ?50%) and containing elements such as Cr, Mo, Cu, Al, Ti, and Nb. According to the main performance, it is further divided into nickel-based heat-resistant alloys, nickel-based corrosion resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys and nickel-based shape memory alloys. For example, Inconel 690, Hatselloy C-276, Haynes 242, Monel 400, Incoloy800 and other nickel-based alloy brands.

food safety

Stainless Steel Is An Important Guarantee For Food Safety?

Food safety begins with strict sanitary conditions, and nickel-containing stainless steel is a high-quality and reliable guarantee for all links in the food chain.

At present, the issue of food supply and food safety is highly valued globally. According to data from the World Health Organization, every year 10% of people get sick from eating contaminated food, and 420,000 people die as a result. Among them, young children are at a particularly high risk.

food safety

Regulatory agencies in various countries attach great importance to food safety, and have introduced relevant laws and regulations to strengthen the supervision of food. For example, the Food Safety Modernization Act in the United States; China amended the Food Safety Act in June 2015, India has strengthened regulations on food contact materials, and Europe has also strengthened the 鈥淢etals and Metals Used in Food Contact Materials and Articles鈥. Alloy Technology Guide.

In the EU, three regulations constitute the food safety regulatory environment:

? “Framework Regulation EC 1935/2004”

The decree stipulates that the materials used in food equipment should not change the taste, quality or color of the food;

These materials should not cause diseases or adversely affect human health;

The decree mainly targets material manufacturers.

? “Machinery Directive EC 2006/42”

  • The regulations stipulate the design and manufacturing methods of food equipment to ensure food safety during processing;
  • This regulation is mainly aimed at equipment manufacturers.

? “Food Hygiene Regulation EC 852/2004”

  • In the preparation process from farm to table, focus on maintaining food safety and maintaining hygienic conditions;
  • It is aimed at food operators, but it also aims to make material and equipment manufacturers accountable.

In short, the purpose of these regulations is to make material manufacturers, equipment manufacturers and food operators share the responsibility of ensuring that food is safe to eat from farm to table.

Food safety investments based on sound science and regulations can help achieve sustainable development goals.

Food safety investments based on sound science and regulations can help achieve sustainable development goals and help solve food pollution problems while ensuring that the food industry receives sufficient returns. One of the investments is the use of nickel-containing stainless steel equipment. Many food-related industries (regardless of their commercial scale, involving food processing, catering, or home cooking) benefit from the hygienic properties of stainless steel while maintaining food safety for consumers throughout the value chain.

Nickel-containing stainless steel does not change the taste or color of food, does not contaminate food, and can provide excellent performance for maintaining food safety through easy and effective cleaning and disinfection.

Stainless steel is designed for hygiene

Cleanliness is the key to hygiene. The smooth, shiny stainless steel surface is very easy to clean and can be maintained for a long time. It can withstand wear, shock and temperature fluctuations, while inhibiting the accumulation of dirt and scale.

The self-healing passivation layer naturally formed in stainless steel provides corrosion protection instead of applying a coating, which may be damaged and degraded. The ability of stainless steel to be easily cleaned and disinfected can effectively and simply remove bacteria. Tests have shown that stainless steel has a low bacterial retention capacity, making it a very attractive material in the food industry. Even if it is reused, stainless steel has impeccable cleanliness. Therefore, stainless steel can meet strict hygiene standards at every stage. The corrosion resistance of stainless steel means that it is inert, does not change the taste or smell of food or beverage products, and can resist the lactic acid formed by the fermentation of acidic foods such as milk or tomatoes.

When designing or selecting food industry equipment, “hygiene” covers many aspects. The manufacturing materials must be able to resist the accumulation of process dirt and must be easy to disinfect and clean between production runs. They must not corrode or give food ingredients harmful to human health. Nickel-containing stainless steel provides all these and more. Their formability, machinability, and weldability enable stainless steel to be processed into complex shapes and components, so that it has good tolerances, which is both practical and economically feasible.

Stainless steel is suitable for all kinds of food

Nickel-containing stainless steel can be widely used in the food industry. Almost all food applications use austenitic stainless steel, including milk and beer. Type 304 is a standard material; fish and meat products may require higher grades, such as type 316L (S31603); super austenitic steel can cope with extreme harshness Conditions such as soy sauce production. Its strong corrosion resistance and easy-to-clean characteristics make stainless steel durable and hygienic. These are two very valuable characteristics in food processing.

1) Stainless steel is widely used in the Italian food industry

Stainless steel meets the specifications of the Italian Ministerial Decree of 1973, the Sanitation Regulations concerning packaging, containers, tools and equipment that come into contact with food or substances for personal use. This specification provides a list of stainless steel grades that can be used in the food industry.

Italian cooking is a perfect example of the functionality of stainless steel. With its hygienic properties, corrosion resistance and beautiful surface treatment, nickel-containing stainless steel has played an important role in the Italian food industry that relies on this effective material. For example, stainless steel is widely used for storage of cocoa butter, cocoa butter and chocolate. The manufacturing facility is equipped with stainless steel storage tanks of various volumes and weights. All storage tanks use Type 304 (UNS S30400) stainless steel specially designed for food industry standards.

Italy’s reputation for gastronomy and its world-renowned design advantages extend to its cooking utensils. Stainless steel has a rustic surface treatment, durability and resistance to dents and scratches, making it an attractive choice. By combining functionality, hygiene, design, and flavor retention (an important part of cookware), stainless steel meets strict specifications. The combination of the expertise, know-how and creativity of Italian designers with the beauty of nickel-containing stainless steel enables them to produce high-quality and exquisite cookware.

2) Application of stainless steel in milking industry

In the milking parlor, nickel-containing stainless steel is everywhere. Here, stainless steel serves the marginal market. For dairy farmers, problems such as cow mastitis and milk contamination can be catastrophic. Hygiene is the most important, and pipes, milking equipment and water tanks need to be carefully flushed and disinfected every day. Stainless steel has the properties of anti-corrosion and cleanliness of excrement. It performs well in this harsh environment and helps achieve the purpose of sanitation and disinfection.

Stainless steel is also essential for keeping milk fresh. Monitor the bacterial count in milk. If there is no very strict control of the bacterial count, it may be rejected. When the milk is squeezed out of the cow’s udder at a temperature of 35掳C, it is quickly cooled to 4-6掳C to prevent the growth of bacteria, and is stored in a stainless steel storage tank usually equipped with a stirring rod or agitator for collection. The heat exchanger is an important part of the dairy industry for cooling and heating, and is used to extract heat from raw milk. In some cases, for example, heat is further used in preheating washing water or space heating. The milk tanker on the truck also uses stainless steel to transport the milk from the milking parlor to the factory for further processing.

Whether the milk is pasteurized for drinking, dried as milk powder, or used to make cheese, yogurt, butter or ice cream, stainless steel equipment must be used to meet very strict hygiene standards.

Although duplex alloys are currently used under more stringent conditions, the main grades used are 304L (UNS S30403) and 316L (S31603) stainless steel.

Food safety has very strict requirements for sanitary conditions, and nickel-containing stainless steel is a high-quality and reliable guarantee for all links in the food chain. Today, more than 25% of total nickel production is used in stainless steel products related to the food and beverage industry. In the food and beverage industry, it is an important guarantee in the food supply chain from farm to table.


Posted by WELLGREEN, the sanitary pipe fittings supplier.

Formtracer Avant series

What Is Surface Roughness?

Definition of Surface Roughness

Surface roughness is very important for most surfaces involved in sliding contact. This is because factors such as the original rate of wear and sustained nature are highly dependent on this characteristic. These surfaces are generally load-bearing surfaces, and the roughness needs to be marked to ensure the suitability of the intended use.

roughness

Surface Roughness (SR) is the roughness of surface in our daily measurement, which can be understood as the unevenness of fine pitch and tiny peaks and valleys in the process of processing products, and also important in sanitary pipe fittings

It is usually defined as the tiny distance (wave distance) between two peaks or two trough fingers. In general, the wave distance is within 1mm or less, and it can also be defined as the measurement of micro-profiles, commonly known as micro-error value .

We generally evaluate that there will be a baseline for roughness. The highest point above the baseline is called the peak point, and the lowest point below the baseline is called the valley point.

Then the height between the peak and the valley is expressed by Z; The distance between the microtextures of the processed product We use S to express.

baseline for roughness

Under normal circumstances, the size of the S value is defined in the national verification standard:

00706142327





Evaluation Parameter Relationship

Ra is defined as the average arithmetic deviation (average roughness) of the curve, Rz is defined as the average height of the unevenness, and Ry is defined as the maximum height.

The maximum height difference Ry of the micro-profile is also expressed by Rmax in other standards.

Please refer to the following table for the specific relationship between Ra and Rmax:

Comparison of Ra and Rmax parameters (um)

Table: Comparison of Ra and Rmax parameters (um)


How Is It Formed?

The formation of surface roughness is caused by the machining process of the workpiece. The processing method, the material of the workpiece, and the process are all factors of the surface roughness of the image.

For example: During the electric discharge machining, the surface of the machined part has discharge irregularities.

The processing technology and the material of the parts are different, and there are various differences in the micro marks left on the surface of the processed parts, such as (density, depth, shape change, etc.).


Effect Of Surface Roughness On Workpiece

Workpiece wear resistance Fit stability Fatigue strength Corrosion resistance Tightness Contact stiffness measurement accuracy 鈥 The coating, thermal conductivity and contact resistance, reflection ability and radiation performance, resistance to the flow of liquids and gases, and the circulation of current on the surface of the conductor will all have varying degrees of influence.


Evaluation Basis

Sampling length

The unit length of each parameter, the sampling length is the length of a reference line for evaluating the surface roughness. Under the ISO1997 standard, 0.08mm, 0.25mm, 0.8mm, 2.5mm, and 8mm are generally used as the reference length.

Evaluation length

Consists of N reference lengths. The surface roughness of each part of the surface of the component can not truly reflect the real parameter of roughness on a reference length, but it needs to take N sampling lengths to evaluate the surface roughness. The assessment length under the ISO1997 standard is generally N = 5.

Baseline

The reference line is the contour center line for evaluating the roughness parameter. Generally, there is a least squares midline and a contour arithmetic mean midline.

[Least Squares Midline] is the least squares calculation of the points collected during the measurement process.

[Arithmetic mean centerline of contour] Within the sampling length, make the area of ??the two parts of the contour on the midline equal

In theory, the least square midline is an ideal baseline, but it is difficult to obtain in practical applications, so it is generally replaced by the arithmetic mean midline of the contour, and a straight line with an approximate position can be used instead.


How To Obtain The Surface Roughness Value?

Formtracer Avant series

Formtracer Avant series

The evaluation of surface roughness is increasingly valued in the manufacturing industry. To study the surface roughness, you need to use a special machine, named: surface roughness measuring instrument.

Most of the correct and complete surface roughness measurement methods, although they use a dedicated measuring machine, but in some cases, for quick and low-cost operation, you can also use hand-held kit tools to measure, as shown below:

20200706140957

The roughness comparison sheet is a nickel-based sample made by electroforming. It is ideal for metal processing and is a very effective auxiliary tool.

The functions that can be achieved by the roughness measuring machine are different, the evaluation method is different, and the cost is also different. Choose the most suitable model according to needs of stainless steel sanitary pipe fittings supplier.

J430 stainless steel tubings

JISCO Successfully Developed J430 Antibacterial Sanitary Tubings

JISCO Successfully Developed J430 Antibacterial Sanitary Tubings

After the occurrence of COVID-19, a stainless steel sanitary tubings R&D project with “antibacterial” as the main difficulty was included in the JISCO scientific research work schedule.

J430 stainless steel tubings

J430 stainless steel tubings

After more than three months of hard work, JISCO successfully developed J430 sanitary tubes. The first batch of products has been applied to a tableware manufacturer. The customer response was good, and then an additional 200 tons of orders were added.

The first batch of J430 antibacterial ferritic stainless steel products developed by JISCO has been tested by the Antibacterial Stainless Steel Testing Center of the Chinese Academy of Sciences and has very good antibacterial performance. The two most important indicators, E. coli and Staphylococcus aureus, have reached 99%. The above is much higher than the 95% national standard.

J430 is a kind of copper-containing antibacterial stainless steel, which is a kind of alloy antibacterial stainless steel. When the antibacterial phase is exposed on the surface of the stainless steel, it will combine with the protein of bacteria to denature the protein, thereby killing the bacteria and achieving the effect of antibacterial and bacteriostatic.


430 stainless steel is a general-purpose steel with good corrosion resistance, thermal conductivity is better than austenite, thermal expansion coefficient is smaller than austenite, heat fatigue resistance, the addition of stabilizing element titanium, good mechanical properties of the welded part.

430 stainless steel is used for building decoration, fuel burner parts, household appliances, and home appliance parts.

430F is a steel grade with easy cutting performance added to 430 steel, which is mainly used for automatic lathes, bolts and nuts.

430LX adds Ti or Nb to 430 steel, reduces C content, improves processing performance and welding performance, and is mainly used for hot water pipes, hot water supply systems, sanitary appliances, household durable appliances, etc.