For spring washers and spring washers, according to the national standard, 60, 70 and 65Mn steels in GB699-1999 "Quality Carbon Structural Steel" are generally selected.
There are 9 flat washer standards in China, which were approved for release from 2000 to 2002 GB/T 97.3-2000, GB/T 5286-2001, GB/T95-2002, GB/T 96.1-2002, GB/T 96.2 -2002, GB/T97.1-2002, GB/T97.2-2002, GB/T97.4-2002 and GB/T5287-2002 flat gasket standards.
According to the performance level of flat washers, I recommend using materials:
For the 100HV class available with ST12, ST13 and Q235, Q215, Q195, etc., the surface hardness can reach about 110HV;
For 140HV grades available 08F, 08Al and 10, 10F, etc., the surface hardness can reach 140HV;
For the 200HV and 300HV grades, 45, 50, 60, 70 or 65Mn steels should be used. They can be quenched and tempered by heat treatment to 200-300HV and 300-400HV technical requirements.
Flat pad
Due to the standard, 100 HV, 140 HV class plain washers can be made of mild steel. Most of the general enterprises use Baosteel materials when selecting materials, which facilitates cold stamping. The Q/BQB403-2003 Baosteel standard is briefly described below.
There are major changes in the "Cold Rolled Low Carbon Steel Sheet and Strip" and Q/BQB403-2003 corporate standards compared to the BZJ407-1999 standard:
(1) The brand number was modified and integrated. There are 8 commonly used brands and 5 integrated products. St12 changed to DC01; ST13 to DC03; St14, St15 to DC04; BSC2 to DC05; St16, St14-T, BSC3 to DC06.
(2) The surface quality level was modified from two to three:
Higher grade finishing surface (FB), the surface allows a small number of defects that do not affect the formability and coating, plating adhesion, such as minor scratches, indentation, pitting, roller printing and oxidation color.
The better of the two sides of an advanced finished surface (FC) product has no visible defects on the naked eye and the other side must meet at least the FB requirements.
The better side of the super-finished surface (FD) product must have no imperfections, ie it must not affect the appearance quality after painting or the appearance quality after electroplating, and the other side must at least meet the requirements of FB.
(3) The surface structure was modified from four to two, and the control value of the surface roughness was increased. The average roughness Ra when the surface structure was a matte surface (D) was 0.6 μm.
(4) The regulations for Si and residual elements in the chemical composition of five brands were eliminated, and the contents of elements such as C, S, and Alt were modified.