What is the material selection principle of stainless steel screws? Seek popular science

Stainless steel screw material selection principle:

1. Requirements for the mechanical properties of stainless steel screw materials, especially in terms of strength;

2. The requirements of the working conditions for the corrosion resistance of the material;

3. The requirements of the working temperature on the heat resistance of the material (high temperature strength, oxidation resistance);

4. Requirements for material processing performance in terms of production technology;

5. Other aspects, such as weight, procurement, and many other factors should be considered.

Stainless steel generally refers to steel that has the ability to resist the corrosion of air, water, acids, alkali salts or other media. Depending on the composition of the alloy, the focus is on stainless steel and acid resistance. Some steels, although rustless, are not necessarily acid-resistant, and acid-resistant steels are generally stainless steel.

The main austenitic stainless steel used in the production of fasteners is austenitic stainless steel, and in people's daily life, the stainless steel often referred to is also austenitic stainless steel. The stainless steel fasteners we use are mainly made of austenitic and "low nickel" 201.

The selection of stainless steel materials is mainly considered from the following five aspects: 1. Requirements for stainless steel screw materials in terms of mechanical properties, especially strength; 2. The requirements of the working conditions for the corrosion resistance of the material 3. The requirements of the working temperature for the heat resistance of the material (high temperature strength, oxidation resistance); 4. Requirements for material processing performance in terms of production technology; 5. Other aspects, such as weight, procurement, and many other factors should be considered. The hardness of the stainless steel screws of the fixed hardware manufacturer is very high, because the materials used are foreign, and it is also more reasonable!

Stainless steel screws.

BAI silk has strong anti-rust and anti-corrosion properties, and is widely used

In outdoor and often rainy places, the stainless steel screws we refer to are only a general term for a material, and the details can usually be divided into the following categories:

201 stainless steel screws.

Material Grades:; However, the 201 material referred to in the domestic market usually does not meet this standard, and the default refers to the ordinary stainless steel material, with a nickel content of less than 1%, which is used in places with low requirements for rust resistance, such as indoor places that do not contact with water, and is also the cheapest, equivalent to half of the 304 material.

304 stainless steel screws.

Elemental content: Carbon C : Silicon si :

Chromium Cr: Manganese Mn: Nickel Ni:

Phosphorus p : Sulfur s : Among them, nickel is the most important element to detect whether it is authentic 304 material, as long as the nickel element is greater than 8%, then we can basically conclude that it is 304 material.

Among them, 304 material is the most commonly used stainless steel screw.

316 stainless steel screws.

Material grade: 06Cr17Ni12Mo2, the corrosion resistance is better than that of 304 stainless steel, and it has good corrosion resistance during use. And 316 stainless steel is also resistant to the erosion of the ocean and the aggressive industrial atmosphere. **It is also much higher than the first two.

1. Ferritic stainless steel. First of all, the 430 model stainless steel material belongs to ordinary chrome steel, the corrosion resistance and heat resistance will be better than the 410 model screws, more magnetic, but it can not be strengthened by heat treatment, so the 430 model stainless steel material is very suitable for corrosion resistance and heat resistance, its hardness is not very good.

2. Martensitic stainless steel. The 410 model and 416 stainless steel materials on the market can be strengthened by heat treatment, after the heat treatment is strengthened, the hardness of stainless steel screws is generally 32 to 45HRC, and the machinability used is also relatively good, and the 416 model stainless steel material has a very high sulfur content, which is an easy-to-cut and easy-to-cut hardware fitting.

3. Austenitic stainless steel. Our more common screw names are 302, 303, 304 and 305, and the so-called 18-8 model austenitic stainless steel is generally these four models. Whether it is corrosion resistance or mechanical properties are very similar, the stainless steel screws used are not exactly the same manufacturing process, and the way used also determines the specifications and shapes of stainless steel screws, and also determines the number of stainless steel screws it manufactures.

Stainless steel screw materials are available in the following types:

1 Austenitic steel.

1)1cr17mn6ni15n；(2)1cr18mn8ni5n；(3)1cr18ni9；(4)1cr18ni9si3；(5)0cr18ni9；(6)00cr19ni10；(7)0cr19ni9n；(8)0cr19ni10nbn；(9)00cr18ni10n；(10)1cr18ni12；（11) 0cr23ni13；(12)0cr25ni20；(13) 0cr17ni12mo2；(14) 00cr17ni14mo2；(15) 0cr17ni12mo2n；(16) 00cr17ni13mo2n；(17) 1cr18ni12mo2ti；(18) 0cr18ni12mo2ti；(19) 1cr18ni12mo3ti；(20) 0cr18ni12mo3ti；(21) 0cr18ni12mo2cu2；(22) 00cr18ni14mo2cu2；(23) 0cr19ni13mo3；(24) 00cr19ni13mo3；(25) 0cr18ni16mo5；(26) 1cr18ni9ti；(27) 0cr18ni10ti；(28) 0cr18ni11nb；(29) 0cr18ni13si4

2 Austenitic – ferritic steel.

30）0cr26ni5mo2；（31）00cr18ni5mo3si2；

3 Ferritic steel.

32）0cr13al；(33) 00cr12；(34)1cr15；(35)1cr17；(36)1cr17mo；(37)00cr17mo； (38)00cr18mo2；(39)00cr30mo2；(40)00cr27mo

4 martensitic steel.

41）1cr12；（42）0cr13；（43）；1cr13；（44）2cr13；（45）3cr13；（46）4cr13；（47）3cr16；（48）7cr17

5. Precipitation hardening section steel.

49）0cr17ni7al

The main austenitic stainless steels on the market now: 304 (OCR18NI9), 321 (1Cr18Ni9Ti), 304HC (OCR18NI9CU2), 316 (OCR17NI12MO2), 316L (0OCR17NI12MO2), 317 (OCR18NI13MO3).

Some areas may be called different, and the quality of this piece of Qingdao Xiangyi is doing well for reference.

The main raw materials are austenitic SUS and "low-nickel" 201.

Kunshan Dongluo professional stainless steel screw production material, 304 316 410 specifications are complete, good quality and low price,

Back to 630: The most commonly used precipitation-hardening stainless steel model is also commonly called 17-4; 17%cr，4%ni。¤▆

Stainless steel screws have the following performance characteristics:

1. Mechanical properties.

As the name suggests, stainless steel screws must be made of stainless steel screws and wire piers, and then the screws with tooth threads are rubbed. Many of the properties of stainless steel screws are related to stainless steel materials. Considering the properties and structure of stainless steel, understand the properties of stainless steel materials.

So as to understand that stainless steel has good mechanical properties such as anti-rust, anti-corrosion, and high temperature resistance, then stainless steel screws certainly have these good mechanical properties. With the stainless steel material material is getting better and better. The mechanical properties of stainless steel screws produced by the screw industry are getting better and better.

Anti-rust and anti-corrosion ability, and high temperature and high pressure are getting stronger and stronger.

2. Physical properties.

Comparison of the physical properties of stainless steel and carbon steel, the density of carbon steel is slightly higher than that of ferritic and martensitic stainless steels, but slightly lower than that of austenitic stainless steels. The resistivity increases in order of carbon steel, ferritic, martensitic and austenitic stainless steels. The order of the linear expansion coefficient is similar, with austenitic stainless steel being the highest and carbon steel being the smallest. Carbon steel, ferritic and martensitic stainless steels are magnetic, austenitic stainless steels are non-magnetic, but they will be magnetic when they are formed by cold work hardening into a stenite phase transition, and this martensitic structure can be eliminated by heat treatment to restore its non-magnetism. Compared with carbon steel, austenitic stainless steel has the following characteristics:

1) High electronegative rate, about 5 times that of carbon steel.

2) The large linear expansion coefficient is 40% larger than that of carbon steel, and with the increase of temperature, the value of the expansion coefficient of stainless steel screw wire also increases accordingly.

3) Low thermal conductivity, about 1 3 of carbon steel.

3. Mechanics.

Regardless of stainless steel plate or heat-resistant steel plate, austenitic steel plate has the best comprehensive performance, which has sufficient strength, excellent plasticity and low hardness, which is also one of the reasons why they are widely used. Austenitic stainless steel is similar to most other metal materials, its tensile strength, yield strength and hardness increase with the decrease of temperature; Plasticity decreases as the temperature decreases. Its tensile strength grows relatively uniformly in the temperature range of 15 to 80 °C.

What's more: the impact toughness of stainless steel screws decreases slowly as the temperature decreases, and there is no brittle transition temperature. Therefore, stainless steel can maintain sufficient plasticity and toughness at low temperatures.

Fourth, heat resistance.

Heat resistance refers to the thermal stability of both oxidation resistance or gas medium corrosion resistance at high temperatures, and sufficient strength at high temperatures, i.e., thermal strength.

There are many types of stainless steel materials, but the important ingredient is to add elements such as nickel and chromium to the steel, which changes the properties.