4130 structural steel has high strength and toughness, high hardenability, critical quenching diameter of 15~70mm in oil; The thermal strength of steel is also good, and it has sufficient high temperature strength below 500℃, but its strength decreases significantly at 550℃. The welding is quite good when the alloy element is at the lower limit, but the weldability is medium when it is close to the upper limit, and it needs to be preheated to more than 175℃ before welding. The steel has good machinability and medium plasticity during cold deformation. During heat treatment, there is the first type of temper brittleness in the range of 300~350℃; Tends to form white spots.
This steel is usually used in the tempered state, when the carbon content is the lower limit of steel can also be used as a high core strength of carburized steel. In the medium machinery manufacturing industry, it is mainly used to manufacture tempering parts with large cross section and working under high stress conditions, such as shafts, mainshafts and control wheels, bolts, stud bolts, gears, etc. In the chemical industry, it is used to manufacture welding parts, welding structures composed of plates and pipes, and high-pressure catheters with a temperature of no more than 250℃ in the medium containing nitrogen and hydrogen; In the steam turbine and boiler manufacturing industry, it is used to manufacture fasteners for work below 450 ° C, flanges and flange covers under high pressure below 500 ° C.