Heat treated high strength fastener should be quenched and tempered according to the technical requirements. The purpose of heat treatment and tempering is to improve the comprehensive mechanical properties of fasteners to meet the specified tensile strength and yield ratio of products. Heat treatment process has a vital impact on high-strength fasteners, especially its internal quality. Therefore, in order to produce high-quality high-strength fasteners, we must have advanced heat treatment technology and equipment. Due to the large production capacity and low price of high strength bolts, the thread part is a relatively fine and precise structure, so the heat treatment equipment must have the ability of large production capacity, high degree of automation and good heat treatment quality. The reaction produces some oxidizing gases, such as rust on the surface of steel wire, which is composed of iron carbonate and hydroxide. After heating, it will be decomposed into CO2 and H2O, thus aggravating the decarbonization.
The results show that the decarburization degree of medium carbon alloy steel is more serious than that of carbon steel, and the fastest decarburization temperature is between 700-800 ℃. Because the adhesion on the surface of steel wire decomposes rapidly to synthesize CO2 and H2O under certain conditions, it is necessary to protect the top of thread from decarburization during quenching and heating, and appropriately cover the decarburized fastener of raw materials, so as to adjust the advantage of protective atmosphere in the mesh belt furnace to be basically equal to the original carbon content of the coated parts, so as to make the decarburized fastener slowly return to normal For the original carbon content, the carbon potential should be set at 0.42% – 0.48%, and the carbon coating temperature is the same as quenching heating, so it can not be carried out at high temperature, so as to avoid coarse grain and affect the mechanical properties.
Fastener High Strength Yellow Black Carbon Steel Brass Heavy Hex Bolt Mark: According to customer’s requirement. Materials: Carbon Steel, Stainless Steel 304&316, Carbon Steel, Brass Surface treatment/Finish: Plain, Zinc Plated Size: M2.5-M72( DIN) 3/16”-3” (ASTM) Grade: Grade8.8,10.9,12.9,A2-70, A2-80, A4-70, A4-80 Quality: Top high quality Anticorrosive Performance: Salt Spray Test Reach 1000-2000 Hours Application: Marchinery, Chemical […]
A325 Heavy Hex Bolt And Nut Standard: ANSI Size: 5/8-11 X 1 1/4″, 5/8-11 X 2″, 5/8-11 X 8″ Material: Carbon Steel Grade: A307 Type B; A325 T/M; A490 Finish:Zinc Plated, Black oxide, H.D.G., Geomet Trade Term: FOB/ CIF/ CFR/ CNF/ EXW/ DDU/ DDP Heat Treated High Strength Fastener Application: Structural Steel Market: South & north America/ Europe/ East & South east […]