24 July 2021 Structural Steel Bar
Q235 Structure Steel Bar
Q235 steel is a kind of carbon structural steel. It is equivalent to the A3 and C3 steel in the old standard GB700-79 grades, and is a grade used in Russia's TOCT. The Q in its steel number represents yield strength. Normally, the steel is used directly without heat treatment.
According to the GB/T 700-2006 standard, carbon structural steel Q235 is divided into four grades: A, B, C, and D according to metallurgical quality. The chemical composition of each grade of steel is
Q235 is divided into four levels: A, B, C and D (GB/T 700-2006)
Q235A grade contains C ≤0.22% Mn ≤1.4% Si ≤0.35% S ≤0.050 P ≤0.045
Q235B grade contains C≤0.20% Mn≤1.4% Si ≤0.35% S ≤0.045 P ≤0.045 (With the consent of the purchaser, the carbon content may not exceed 0.22%)
Q235C grade contains C ≤0.17% Mn ≤1.4% Si ≤0.35% S ≤0.040 P ≤0.040
Q235D grade contains C ≤0.17% Mn ≤1.4% Si ≤0.35% S ≤0.035 P ≤0.035
There are many examples in China of applying the intense quenching process of low carbon martensitic steel to manufacture cold work molds.
Double-layer glow ion penetration metal technology is used to carry out Mo-Cr co-infiltration on the surface of the steel, followed by supersaturated carburizing, quenching and tempering composite treatment. The thickness of the Mo-Cr bent layer is more than 100 microns, and the surface Mo content Up to 20%, Cr content reaches 10%, supersaturated carburizing surface carbon content exceeds 2.0%, surface composition is close to molybdenum series high speed steel, surface hardness after quenching and tempering is as high as 1300HV, exceeding general metallurgical high speed steel. Wear tests show that the friction coefficient increases with the increase of contact stress, and the average relative wear resistance is 2.2 times that of GCr15 carburized and quenched steel.
1. Can be used for various grinding tool handles and other unimportant grinding tool parts.
2. GCr15, 9SiCr, T8 and 45 steel were used in the past. Due to the phenomenon of mold bite and mold sticking in the workpiece, it was difficult to punch out the forging blank from the mold, resulting in plastic deformation, bending and breakage of the punch, and a short service life. Approximately 800 to 1,200 bolts can be punched with 10 pieces of punches; Q235 steel is later used as the punch material. After quenching, it can be used directly without tempering. The hardness is 36 to 40HRC. Each ten pieces of punches can punch more than 2,000 bolts without failure. The form is plastic deformation, which solves the problem of the punch breaking during use and ensures the operator's personal safety.