Introduction to basic knowledge of flat washers

In our lives, flat washers are also called flat washers. They are mainly stamped out of iron plates. They are generally shaped like a flat washer with a hole in the middle. The hole size specifications are generally determined according to customer requirements.
There are 9 flat gasket standards in my country. From 2000 to 2002, GB/T97.3-2000, GB/T5286-2001, GB/T95-2002, GB/T96.1-2002, and GB/T96.2 were approved and released respectively. -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, the author recommends the following materials:
 For 100HV grade, ST12, ST13, Q235, Q215, Q195, etc. can be used, and the surface hardness can reach about 110HV;
For 140HV grade, 08F, 08Al, 10, 10F, etc. can be used, and the surface hardness can reach about 140HV; for 200HV and 300HV grade, 45, 50, 60, 70 steel or 65Mn steel should be used, which can be achieved through heat treatment, quenching and tempering. Technical requirements for 200~300HV and 300~400HV.
Since according to the standard, flat washers of 100HV and 140HV grades can be made of mild steel. When general enterprises choose materials, most of them use Baosteel materials to facilitate cold stamping. The following is a brief description of Baosteel standards.
  "Cold Continuous Rolling Low Carbon Steel Plate and Steel Strip" and enterprise standards have major changes compared with the BZJ407-1999 standard:
 (1) The brand names have been modified and integrated. The commonly used 8 types of brands have been integrated into 5 types. St12 is changed to DC01; ST13 is changed to DC03; St14 and St15 are changed to DC04; BSC2 is changed to DC05; St16, St14-T, and BSC3 are changed to DC06.
  (2)The surface quality levels are modified from two to three:
 Higher-level finished surface (FB), the surface is allowed to have a small number of defects that do not affect the formability and coating and plating adhesion, such as slight scratches, indentations, pitting, roller marks and oxidation color, etc.
 The better of the two sides of a high-grade finished surface (FC) product has no obvious defects visible to the naked eye, and the other side must at least meet the requirements of FB.
 The better side of the two sides of the ultra-high-grade finished surface (FD) product must not have any defects, that is, it cannot affect the appearance quality after painting or the appearance quality after electroplating. The other side must at least meet the requirements of FB.
  (3) The surface structure is modified from four types to two types, and the control value of surface roughness is increased. When the surface structure is pitted (D), the average roughness Ra is 0.6 μm.
 (4) The regulations on Si and residual elements in the chemical composition of the five grades have been cancelled, and the contents of C, S, Alt and other elements have been modified.