1800MPa-grade hot forming steel as well as hot stamping forming method and application thereof

Abstract

The invention provides 1800MPa-grade hot forming steel as well as a hot stamping forming method and application thereof, and belongs to the technical field of hot forming steel. The 1800MPa-grade hot forming steel provided by the invention comprises the following chemical components: 0.28 to 0.32 percent of C, 0.2 to 0.3 percent of Si, 1.5 to 1.7 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.01 percent of S, 0.002 to 0.0035 percent of B, 0.15 to 0.25 percent of Cr, 0.02 to 0.05 percent of Al, less than or equal to 0.03 percent of Ti, less than or equal to 0.005 percent of N, 0.04 to 0.055 percent of Nb, 0.15 to 0.25 percent of V and the balance of Fe and impurities. The tensile strength and the ductility of a 1800MPa-grade hot forming steel member are guaranteed through the combined action of C, Si, Mn, P, S, B, Cr, Al, Ti, N, Nb and V with specific contents and tempering through waste heat after quenching.

Description

technical field [0001] The invention relates to the technical field of hot forming steel, in particular to a 1800MPa grade hot forming steel and its hot stamping forming method and application. Background technique [0002] With the rapid development of the automobile industry, lightweight and safety have become the main direction of the development of the automobile industry. By using a large number of hot-formed steel plates in the body-in-white, the thickness of the steel plates is reduced under the premise of ensuring the safety of the body, and the purpose of reducing weight is achieved under the premise of ensuring safety. At present, low-carbon Mn-B steel plates are the most widely used. After quenching, the structure becomes complete martensite, and the strength is between 1300 and 1500 MPa. It is mainly used in A-pillars, B-pillars, and door anti-collision beams. In the past 10 years, higher-level hot-formed steel (1800-2000MPa) has been researched. [0003] For e...

AI Technical Summary

Problems solved by technology

[0003] For example, Chinese patent CN107354385A discloses a method for preparing ultra-high-strength hot-formed steel for automobiles. The composition of the hot-formed steel is: C 0.5-0.6%, Mn 0.5-2%, Si 1.5-2.5%, Cr 1-3% , Al 1~2%, Nb 0.01~0.03%, B 0.001~0.005%, the balance is iron and no impurities, but its alloy elements are high, so it is difficult to promote in the automotive industry

Chinese patent CN102296242A discloses a heat treatment method for high-strength and toughness hot-formed steel sheets for automobiles. The composition of the hot-formed steel sheets is: C 0.20-0.40%, Si 0.10-0.50%, Mn 1.0-2.05%, P≤0.02%, Nb 0.02~0.06%, Ti 0.01~0.05%, Cr 0.1~0.5%, B 0.001~0.005%, Al 0.01~0.1%, N≤0.01%, although the hot-formed steel plate has high-strength steel toughness, its strength is also relatively obvious reduction of

Chinese patent CN103361560A discloses a cold-rolled thermoformed steel plate and its production method. The composition of the thermoformed steel plate is: C 0.22~0.25%, Si 0.20~0.30%, Mn 1.20~1.40%, P80 = about 5.7%, the composition design system is B-containing system, which is a complete martensitic structure, but its strength and elongation need to be improved, which has not met the requirements for the use of auto parts (strength not less than 1800MPa and elongation not less than 6%)

Chinese patent CN106119693A discloses thin hot-formed steel with tensile strength ≥ 2100MPa directly rolled by thin slab and its production method. The composition of hot-formed steel is: C 0.41-0.50%, Si 0.45-0.65%, Mn 1.6-2.0%, P ≤0.006%, S≤0.004%, Al 0.015~0.06%, Cr 0.50~0.65%, B0.004~0.005%, Ti 0.046~0.060% or Nb 0.046~0.060% or V 0.046~0.060%, or two of them The above compound, Mo 0.036~0.60%, Ni 0.21~0.35%, N≤0.004%, the rest is Fe and no impurities; the carbon content of this patent is high and a large amount of alloying elements are added, so that the carbon equivalent is ≥0.78, which seriously affects its performance. High solderability and production costs

It can be seen that the steel plate is a complete martensitic structure after hot forming. Although the strength of the formed part has been improved, its elongation is still difficult to break through 7%, resulting in the deformation of the parts during the collision process. Safety and Increased Risk to Occupants

Images