High manganese steel for automobiles and manufacturing method thereof

Abstract

The invention discloses automotive high manganese steel. The steel comprises the following chemical components in percent by weight: 0.55-0.64 percent of C, 0-0.01 percent of Si, 23.5-24.4 percent of Mn, 0-0.015 percent of P, 0.45-0.54 percent of Nb, 0.02-0.06 percent of Als, 0-0.01 percent of S, 0-0.003 percent of N and the balance of Fe and inevitable impurities. The method for manufacturing the steel comprises the following steps of controlling temperature for heating a continuous casting billet to be 1220-1280 DEG C, controlling temperature of rough rolling to be 1050-1100 DEG C, controlling the finishing temperature to be 910-950 DEG C through finish rolling, rolling at the temperature of 680-720 DEG C, controlling a total reduction rate to be 67-80 percent through cold rolling, and controlling the continuous annealing temperature to be 800-850 DEG C through controlled cooling. The steel component design is optimized, and the production process is controlled, so that high-strength Fe-Mn-C-Nb TWIP steel is obtained and can be used for punching automotive safety parts or structural components. The obtained product has relatively high yield strength and plasticity, and the safety of parts in the actual vehicle using process is improved when the requirement for forming complex parts is met.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgical materials, in particular to a high manganese steel for automobiles and a manufacturing method thereof. Background technique [0002] The use of high-strength steel with good formability is the main development trend of steel for vehicles. Among them, TWIP steel (Twin Induced Plasticity Steel) is an austenitic steel with low stacking fault energy. A large number of deformation twins delay the formation of necking, and then have excellent strong plasticity, high strain hardening, and high energy absorption capacity (at 20 ° C, the absorption energy reaches 0.5J / mm). Twinning is the main mechanism affecting the plastic deformation of TWIP steel, and its mechanical properties mainly depend on the stacking fault energy, which determines whether the main deformation mechanism is slip, cross-slip, partial dislocation slip, twin deformation, or strain-induced horsepower. body phase transformat...

AI Technical Summary

Problems solved by technology

Manganese and aluminum can effectively increase the stacking fault energy of the alloy, promote the TWIP effect, and inhibit the TRIP effect. However, for industrial production, aluminum is easy to oxidize, and it is easy to generate oxide residues to block the casting port during steel plate casting. It is beneficial to the industrial production of TWIP steel, and silicon will reduce the stacking fault energy of the alloy, resulting in an increase in the number of stacking faults and inhibiting the TWIP effect. At the same time, excessive silicon content will affect the surface quality of the steel plate and reduce the hot rolling performance of the steel plate

Therefore, among the above-mentioned three TWIP steel components, Fe-Mn-C series is more suitable for industrial production, but the existing Fe-Mn-C series TWIP steel generally has extremely high elongation, and the elongation exceeds 60%. In the manufacture of automotive safety parts and structural parts, such a high elongation is not actually needed; moreover, the yield strength of the steel is low, which will adversely affect the safety structural parts of the car

Images