Difference Between A2 and A4 Stainless Steel Screws
A2 Stainless Steel Screws and A4 Stainless Steel Screws are two kinds of stainless steel fasteners made of different materials after cold heading, rolling teeth, and passivation cleaning. Because they have different chemical compositions and different mechanical properties, so their application areas are different.
A4 stainless steel screws and A2 stainless steel screws are two different materials after cold heading forming, rolling teeth, and passivation cleaning of stainless steel fasteners. Because they have different chemical compositions and mechanical properties, their application areas are also different.
All Type Stainless Screws Factory
- Ding Fasteners
- N0.52 Qinfen Rd, Haiyan Zhejiang China
- [email protected]
- 0086-13819377033
- Walter Chou
What A2 and A4 Stainless Steel Bolts Chemical Composition
A2 (304) Chemical Composition
A2 stainless steel screws are made of SS304 disc element material, because the nickel content is 8% The chromium content is 18%, so it is also called 18-8 screws.
In which the nickel content element is very important to determine the corrosion resistance of 304 stainless steel screws directly.
A2 (316) Chemical Composition
A4 stainless steel screws are made of SS316 steel wire material, compared with 304 material, it has a higher nickel content, and the chemical composition contains 2-3% molybdenum content, which is not in the 304 material.
Because of the molybdenum content, 316 screws have better corrosion resistance, especially pitting resistance.
Difference In Tensile Strength Between A2 and A4 Stainless Steel Screws
Both stainless steel A2 and A4 screws will have a substantial increase in tensile strength over the raw material after cold heading. Because of the difference in the tensile strength of the two raw materials themselves, the tensile strength of the screws will also produce a difference in tensile strength after being made.
A2 Stainless Steel Screws Tensile
Stainless steel 304 screws are available as A2-50 and A2-70 screws or bolts, depending on their tensile strength.
A2-50 screws, is a based on 304 stainless steel material, tensile strength of 500mpa and screws, according to our test results, the actual tensile strength of 510-530mpa.
A2-70 screws, are made of high-quality stainless steel 304 material, and the tensile strength reaches 700mpa as well, because of the requirement of tensile strength, so in the selection of raw materials
We will choose the stainless steel 304 material with slightly higher copper content. The actual tensile strength result is around 730mpa.
A4 Stainless Steel Screws Tensile
Stainless steel 316 screws are available as A4-70 and A4-80 screws or bolts, which called are high-tensile stainless steel screws.
A4-70 screws are made of stainless steel 316 wire after clod punching, tensile strength will be above 700 Mpa screws, according to our test results, the actual tensile strength of 725-735mpa.
A8-80 ss screws material is the top quality of ss 316 which produce by big factories, the basic material tensile should be the same as ASTM A276 standard. after our production, the tensile strength reached 800mpa as well, The actual tensile strength result is around 830mpa.
304 and 316 Stainless Steel Screws Application
A2 stainless steel screws are generally used for structures in low-temperature environments. A4 stainless steel screws, because they have more molybdenum than A2 stainless steel screws, have a high-temperature resistance that can reach more than 1,200 degrees Celsius. And the corrosion resistance is also much better than A2 stainless steel screws.
In the same industrial environment, especially seawater, high temperature, high pressure projects, using the same specifications of the A2 stainless steel screws and A4 stainless steel screws, after a period of operation, the surface of the A2 stainless steel screws will appear rust spots or deformation, but the A4 stainless steel screws have no change.
Applications of 304 Stainless Steel Screws
Mechanical equipment, for fixing components, assembling equipment and connecting structures
Construction field, used in the construction of steel and wood structure connection, has good tensile strength
The photovoltaic mounting system, 304 stainless steel screws can be perfectly combined with aluminum fittings, no rust on aluminum parts, durable.
Application of 316 Stainless Steel Screws
Medical equipment, for the connection of medical equipment, surgical instruments and so on.
Food processing, food processing equipment, and tiger hall equipment.
Chemical and petrochemical, pipe fittings, storage tanks and equipment such as reactors.
Marine and ship, ship hulls, ship equipment and marine platforms.
Environmental protection and water treatment, sewage treatment equipment, and water treatment equipment.
Conclusion
General general use of the choice of A2 stainless steel screws, because it can achieve the use of the purpose and cheap, in the use of harsh environments, especially high temperature and high pressure, offshore work, we recommend the use of A4 stainless steel screws.
Contact the Experts
- Ding Fasteners
- N0.52 Qinfen Rd, Haiyan Zhejiang China
- [email protected]
- +86-573-86221432