42CrMo4 Bolt grade 10.9 &8.8 Material-42CrMo4 SUPPLIER

42CrMo4 Bolt grade 10.9 &8.8 Material——High-strength bolt raw material

Most of the high-strength bolts for wind power are grade 10.9, and a few are grade 8.8. For 10.9 grade high-strength bolts, the tensile strength should be 1250MPa≥ Rm≥1030MPa, the elongation should be A≥9%, the reduction of area should be Z≥48%, and the low temperature impact Energy (-45℃):KV2≥27J.

What makes the fasteners lose?

Selection of bolt raw materials.
Defects in the manufacturing process, resulting in easy breakage at the bottom of the thread during the test;
The processing procedure is inverted (rolling thread before heat treatment), resulting in insufficient thread pressure and pre-tightening force;
The unreasonable control of heat treatment temperature and time leads to insufficient metallographic structure and affects the final performance of the product.

Identification Grade Mark	Specification	Fastener Description	Material	Nominal Size Range (in.)	Mechanical Properties
					Proof Load(psi)	Yield Strength Min (psi)	Tensile Strength Min (psi)
8.8	ISO R898 Class 8.8	Bolts, Screws, Studs	Alloy Steel, Quenched&Tempered	All Sizes thru 1-1/2	85000	92000	120000
10.9	ISO R898 Class 10.9				120000	130000	150000

As an Alloy Steel, 42CrMo4 is a commonly used raw material of high-strength bolts, especially for grade 10.9 and 8.8, the alloy steel should be Quenched and Tempered.

42CrMo4 Bolt grade 10.9 &8.8 Material