Structure Description of Stainless Steel Tube Mill

Stainless steel tube mill is a special equipment for forming and welding various stainless steel pipes, alloy steel pipes and carbon steel pipes, which is suitable for liquid transportation pipelines in petroleum, chemical, metallurgical and other industries.

Structure of Stainless Steel Tube Mill:

1. Main Forming Machine: It is composed of two parts, the base, and the cross beam; the motor and reducer are mounted on the base, and there is a fixed frame and a movable frame installed on the cross beam by bolts.

2. Fixture: It is composed of three parts: bracket, chuck, and clamping mechanism; the bracket is fixed on the base, and the stands are adjustable; the chuck is installed in the end face of the bracket; the clamping mechanism is mounted on the movable frame.

3. Transmission & Electrical Control Systems: The motor drives the pulley to rotate the spindle and drive the fixture to move longitudinally or laterally to realize the welding process of the workpiece.

4. Hydraulic & Pneumatic Systems: The main function is to keep the workpiece stable during the heating process and guarantee it to meet certain accuracy requirements; At the same time, the flow rate of cooling water can be regulated to adjust the temperature of the workpiece to control the product’s quality.

5.Safety Protection Device: It is mainly composed of overload protection device and safety interlock device.

What Is The Difference Between Food Grade 304 Stainless Steel And Ordinary Stainless Steel

Food grade stainless steel refers to the stainless steel material that meets the requirements of the National Standard of the People's Republic of China / Sanitary Standard for Stainless Steel Food Containers, GB 9684-88, and its lead chromium content is much lower than that of ordinary stainless steel.

Indicator regulations

Food grade stainless steel refers to the part of food machinery that comes into contact with food and must meet certain food safety requirements. Because the food production process uses a lot of acid and alkali, and stainless steel contains chromium, unqualified stainless steel, will dissolve all kinds of chromium, toxic; and it is required to limit the content of various alloy impurity elements such as lead and cadmium.

The difference between food grade stainless steel and 304 stainless steel

When stainless steel products migrate in excess of heavy metals during use, they may endanger human health.

Therefore, the production of stainless steel cookware requires a balance between corrosion protection and safety. If the content of nickel and chromium is high, the anti-corrosion function is enhanced, but the amount of nickel and chromium precipitated will also increase, which means the safety risk is increased.

Because of this, "Stainless Steel Products" (GB9684-2011) national food safety standards, strict regulations on the precipitation of chromium, cadmium, nickel, lead and other heavy metals in the cookware.

Why does the national standard not stipulate the migration limit of manganese?

One reason is that with the increase of manganese content in stainless steel, it is accompanied by the loss of functions such as corrosion resistance and rust resistance of the cookware. Once the manganese content is high to a certain value, the product cannot be used as a cookware or stainless steel cookware. It is. But even such a high manganese content generally does not affect health.

Therefore, although the national food safety standard does not regulate the manganese content, it is clearly stated that the main part of the food container must be made of stainless steel material in accordance with national standards.

Food grade stainless steel is stainless steel according to GB9684 standard

Food grade stainless steel, also known as "GB9864 stainless steel", is the stainless steel material specified in GB 9684-2011 under the National Standard of the People's Republic of China / Sanitary Standard for Stainless Steel Food Containers. The lead content of this stainless steel is lower than that of ordinary stainless steel. Much more, the product's anti-corrosion performance has also increased, the requirements are: lead (in Pb), mg / L 4% acetic acid soaking solution ≤ 1.0 1.0. Chromium (in terms of Cr), mg / L 4% acetic acid soaking solution Medium ≤ 0.5. Nickel (in terms of Ni), mg/L 4% acetic acid soaking solution ≤ 3.01.0. Tin (in terms of Sn), mg/L 4% acetic acid solution ≤ 0.02 0.02. Arsenic (as As), mg/L 4% acetic acid solution ≤ 0.04 0.04. Note: The soaking conditions are all boiled for 30 min, then room temperature for 24 h.

304 stainless steel is a very common stainless steel, also known as 18-8 stainless steel. Its corrosion resistance is better than 430 stainless steel, corrosion resistance, high temperature resistance, good processing performance, so it is widely used in industrial and furniture decoration industry and food medical industry, such as: some high-grade stainless steel tableware, bathroom kitchen utensils.

304 is a versatile stainless steel that is widely used to make equipment and parts that require good overall performance (corrosion resistance and formability).

In order to maintain the corrosion resistance inherent in stainless steel, the steel must contain more than 17% chromium and more than 8% nickel.

Generally 304 stainless steel is not food grade, and the special processed food grade.

It is well known that stainless steel products related to “edible” must use 304, 316 stainless steel. 316 stainless steel is expensive and is used in high-end equipment such as aerospace and food machinery. The food grade stainless steel used in daily necessities is mostly 304 stainless steel, which has good acid and alkali resistance and strong corrosion resistance.

In comparison, 201, 202 stainless steel (commonly known as high manganese steel) is generally used in industrial products, not for tableware, because it:

● The nickel content is not up to standard, the acid and alkali resistance is poor, and it is easy to rust;

● Excessive manganese content, excessive intake of manganese in the human body can cause damage to the nervous system.

201 stainless steel contains less nickel, less chromium, weaker anti-corrosion performance, more manganese, better acid and alkali resistance, and cheaper price! In order to maintain the inherent corrosion resistance of stainless steel, 201 stainless steel must contain more than 16% chromium, more than 8% Nickel content. The surface is very bright with dark light, and the manganese is high and it is easy to rust. 304 contains more chromium, the surface is matte and does not rust. The two are put together and there is comparison. The most important thing is the different corrosion resistance. The corrosion resistance of 201 is very poor, so the price is much cheaper. And because 201 contains low nickel, the price is lower than 304, so the corrosion resistance is not as good as 304.

In daily life, our chances of getting in contact with stainless steel products are extremely high, and stainless steel electric kettles are one of them. Which are "201" and which are "304"? It is difficult to distinguish ~

Differentiating these different stainless steel materials, the laboratory method is mainly to detect the composition of the substance. For example, the hand-held fluorescence spectrometer, which is more commonly used by us, can quickly analyze stainless steel of different materials and quickly obtain the content of all elements in the metal composition. There will be obvious differences.

In general: food grade stainless steel refers to the stainless steel material that meets the national GB9684 standard and can be in contact with food without causing physical harm. GB9864 stainless steel is in accordance with the national GB9684 standard certified stainless steel material, so GB9864 stainless steel is food grade stainless steel. . At the same time, the so-called 304 stainless steel is not required to pass the national GB9684 standard certification, 304 stainless steel is not equal to food grade stainless steel, 304 stainless steel is not only used in kitchen utensils, but also widely used in industry, the hazard to the human body is unknown. At the time of purchase, regular products will be marked with “food grade 304 stainless steel” on the surface and inner wall of the product, and the product labeled “food grade – GB9684” will be safer.

Summary Of Types And Uses Of Stainless Steel Pipes

Stainless steel pipes are the most common types of pipes in engineering. The common ones are 201 and 304. It has the advantage that other pipes are irreplaceable, and there will be more and more applications in engineering, and the use will become more and more popular, and the prospects are promising.

In some cases, stainless steel pipes are superior, especially thin-walled stainless steel pipes with a wall thickness of only 0.6-1.2 mm, which are safe in high-quality drinking water systems, hot water systems, and water supply systems that put safety and hygiene first. Reliable, hygienic and environmentally friendly, economically applicable. It has been proved by domestic and international engineering practice that it is one of the best, new, energy-saving and environment-friendly pipes for the water supply system. The following is a detailed description of the stainless steel pipe.

ss Pipes

Summary of types and uses of stainless steel pipes

I. Stainless steel decorative tube

1. Material: 201, 304 based, 301, 316 small

2. Uses: Stairs, doors and windows guardrails and other decoration projects, some of which require lower product piping

3. Features: bright surface, brushed or matte, negative

II. Stainless steel product tube

1. Material: 201, 304, 316

2. Uses: bathroom home, product piping, fluid pipe, etc.

3. Features: strict requirements on positive and negative specifications, surface brightness, etc., there will be requirements for bending, expansion, etc.

III. Stainless steel shaped tube

When the number of special-shaped tubes is generally small, the method of forming the secondary tubes of the round tubes (excluding the tank tubes) is adopted, and the number can be customized. Because of different specifications and sometimes lack of molds, it may be necessary to bear the corresponding mold costs.

1. Elliptical tube: positive elliptical tube, flat elliptical tube

2. Groove tube: round tube, square tube, rectangular tube, elliptical tube, etc. can be slotted, generally used for guardrail border card glass

3. Others: triangles, handrails, arches, sectors, door frames, etc.

IV. Stainless steel tube

The appearance of the pattern tube has changed the single appearance of the traditional stainless steel tube, which makes people feel refreshed. Recently, many tube factories have been on the line pattern tube project.

1. Ordinary embossing: a traditional round tube with a section of pressure hoist

2. European embossing: the surface of the pipe is pressed back, auspicious clouds, money and other patterns

V. color stainless steel tube

The surface of the stainless steel tube is coated with a layer of color. Any material specification can be used. The corresponding processing cost is increased by the square on the basis of the pipe. In the past, the color has been painted below four meters. Now the gold, rose gold and black titanium can be painted 6 meters. The color tube needs to reduce the welding probability and adopt the link piece.

VI. Stainless steel composite pipe

1. Stainless steel composite pipe: In the previous two years, there was a composite pipe with surface 304 and inner layer 201. Now that the price of 304 has decreased, the composite pipe has been reduced.

2. Carbon steel composite pipe: surface 201 or 304, internal carbon steel, surface layer thickness of 1.0 or less, generally used for highway guardrail engineering.

VII. Stainless steel industrial pipe

Industrial pipes also have welded pipes and seamless pipes, mainly used in engineering structures, various types of pipes, etc.

What are the classifications of stainless steel pipes?

1 stainless steel tube classified by material

Divided into ordinary carbon steel pipe, high-quality carbon structural steel pipe, alloy structural pipe, alloy steel pipe, bearing steel pipe, stainless steel pipe and bimetallic composite pipe, coating and coating pipe to save precious metals and meet special requirements. Stainless steel tubes are available in a wide variety of applications, with different technical requirements and different production methods.

2 Classification by production mode

According to the production mode, the stainless steel pipe is divided into two types: seamless pipe and welded pipe. The seamless steel pipe can be divided into hot rolled pipe, cold rolled pipe, cold drawn pipe and extruded pipe, etc. Cold drawing and cold rolling are secondary to steel pipe. Processing; welded pipes are divided into straight welded pipes and spiral welded pipes.

3 sorted by section shape

Stainless steel tubes can be divided into round tubes and shaped tubes according to the cross-sectional shape. The special-shaped tube has a rectangular tube, a rhombic tube, an elliptical tube, a hexagonal tube, an eight-sided tube, and various cross-section asymmetric tubes. Shaped tubes are widely used in a variety of structural parts, tools and mechanical parts.

4 sorted by tube end shape

The stainless steel tube can be divided into a light pipe and a wire tube (threaded steel pipe) according to the state of the pipe end. The wire tube can be divided into ordinary wire tube (transporting water, gas and other low pressure tubes, using ordinary cylindrical or conical tube thread connection) and special threaded tubes (oil, geological drilling tubes, for important wire tubes) Special threaded connection) For some special tubes, in order to compensate for the influence of the thread on the strength of the tube end, the tube end is usually thickened (inner thickening, outer thickening or inner and outer thickening) before the wire.

5 sort by purpose

According to the application, it can be divided into oil well pipe (casing, oil pipe and drill pipe, etc.), pipeline pipe, boiler pipe, mechanical structural pipe, hydraulic pillar pipe, gas cylinder pipe, geological pipe, chemical pipe (high pressure fertilizer pipe, petroleum cracking pipe). ) and ships and other tubes.

Stainless steel pipe is a hollow strip of round steel, which is widely used in petroleum, chemical, medical, food, light industry, mechanical instrumentation and other industrial pipelines and mechanical structural components. In addition, when the bending and torsional strength are the same, the weight is light, so it is also widely used in the manufacture of mechanical parts and engineering.

Stainless Steel Welded Pipes Be Used As Heat Exchanger Tubes

In the past five years, the development trend of stainless steel welded pipes has been relatively good, and great progress has been made in all aspects of scale and quality production technology, especially in the field of demand. In addition, as the stainless steel welded pipe process becomes more and more mature, stainless steel seamless pipes can be gradually replaced in many applications, such as heat exchanger equipment pipes, medium and low pressure boiler pipes, and the like.

Stainless steel welded pipe equipment production characteristics: light production equipment, low investment, quick construction, simple welding method, complete product specifications, high dimensional accuracy, small wall thickness deviation, surface smoothness, high yield. In the case of mass production, the welded pipe is 20% lower than the seamless pipe. In recent years, the domestic use of "welding - cold rolling" production of stainless steel pipe technology, the use of cold-rolled coils according to the specifications of the longitudinal shear forming, through a multi-gun argon arc welding machine welded into a tube and then cold rolling (pull), welding The performance index of the seam is basically the same as that of the base metal, and the product quality is obviously improved. Therefore, the advantages of using stainless steel welded pipes instead of stainless steel seamless pipes are becoming more and more obvious.

Advantages of stainless steel welded pipe equipment production: Firstly, in the production process of stainless steel welded pipe, the pipe body is uniformly extruded, and then subjected to on-line bright solid annealing annealing, the surface becomes very smooth, the surface is smooth and easy to expand, and has antifouling function. . This is good for heat dissipation, does not require frequent cleaning, saves time and effort, and saves money. Secondly, the welded pipe is a deep-processed product of the plate, and the advantage of uniform wall thickness is unparalleled, and it can be arbitrarily fixed with high precision. Also, stainless steel is corrosion resistant and has a long service life.

3, stainless steel welded pipe product status: China's industrial stainless steel welded pipe production capacity does not meet the domestic market demand, the existing stainless steel welded pipe equipment unit most of the process equipment does not match, such as lack of heat treatment and - line testing equipment, so that the unit's production capacity can not be fully exerted, Generally, only general decorative pipes can be produced, and the low-grade standard stainless steel decorative welded pipes on the market are oversupplied; the higher standard industrial welded pipes, such as chemical mechanical pipe heat exchanger pipes, can only be produced by a few manufacturers, and the production capacity is seriously insufficient.

Stainless Steel Exchanger Tubes

Can the welded pipe act on the heat exchange equipment?

NO.1, higher standard product tubes are possible. Heat exchanger tubes are indispensable components in tube-tube heat exchange equipment. Heat exchanger tubes are usually selected based on pressure and fluid medium. A misunderstanding of the choice of heat exchanger tubes on the market today is that stainless steel welded pipes cannot be used as heat exchanger tubes, but GB/151-1999 clearly stipulates that when the pipe pressure is ≤ 6.4 MPa, stainless steel welded pipes can be used. In particular, the stainless steel welded pipe production process is now very mature, and it can fully meet the needs of general heat exchanger tubes and exhibit its unique advantages.

NO.2, mature production process, austenitic stainless steel welded pipe will become the first choice

Since the heat exchanger tubes constitute the heat transfer surface of the heat exchanger, the size of the heat exchanger tubes has a large effect on heat transfer. When a small-diameter tube is used, the heat exchange area per unit volume of the heat exchanger is large, the equipment is relatively compact, the metal consumption per unit heat transfer area is small, and the heat transfer coefficient is also high. Although it is troublesome to manufacture, the use of austenitic stainless steel welded pipe as a heat exchange tube can avoid the above problems because the austenitic stainless steel welded pipe has both good corrosion resistance and a smooth surface, and the production process is mature, so the austenitic stainless steel welded pipe It is the first choice for heat exchanger tubes.