There are five types of materials used in fasteners:
• alloy steel
• Carbon steel (low carbon steel and medium carbon steel)
• Stainless steel
• Copper and its copper alloys
• Aluminum and its alloys
1. Alloy steel
Steel containing alloying elements is called alloy steel, which can be divided according to the amount of alloying elements: from the content of alloying elements:
  Low alloy steel: the total amount is less than 5%
  Medium alloy steel: the total amount is 5%-10%
  High alloy steel: the total amount is more than 10%
  The main elements contained in the alloy can be divided into: chrome steel, chrome-nickel steel
     Manganese steel, silicon manganese steel, etc. Related numbers are: 30Cr 35Cr 40Cr
     20CrMn 30CrMo 35CrMoA 20CrMoA 21CrMoA
20CrMovTiB 20CrMoVNbTiB 20CrMoV
21Cr12wMoVNbB Gh2132 35CrMo 42CrMo
2. Carbon steel
• Low carbon steel: the carbon content is less than or equal to 0.25%, the relevant steel grades used are Q215 Q235 Q195 10# 15# 20#
• Medium carbon steel: the carbon content is greater than 0.25% and less than or equal to 0.6%, and the relevant steel grades used are 35# and 45#
• High carbon steel: the carbon content is greater than 0.6%, currently our company does not use high carbon steel for standard parts.
3. Stainless steel
Stainless steel is a material containing alloying elements Cr Ni Ti and other anti-corrosion properties. It is divided into austenitic stainless steel, such as A2 (304 series stainless steel) A4 (316 series stainless steel), 301 and 302 series stainless steel. Austenitic-ferritic Stainless steel such as: 0Cr26Ni5Mo2 1Cr18Ni11Si4AlTi. Ferritic stainless steel, such as: 00Cr12 1Cr17 0Cr3Al. Martensitic stainless steel, such as: 2Cr13 3Cr13 4Cr13
4. Copper and copper alloy
Copper and copper alloys commonly used in fasteners are:
  T2 H63 HPb59-1
  QSn6.5-0.4 QSi1-3
  QAl10-4-4
5. Aluminum and aluminum alloy
Aluminum and aluminum alloys commonly used in fasteners are:
  5A02 2B11
  2A90 7A09
  5A12 5A05
  5A43