3 results about "Bainite" patented technology

The invention provides a thick steel board exhibiting low tensile ratio and high toughness, which contains following elements: 0.03-0.15 weight percent of C, less than 1.0 weight percent of Si (0 weight percent not included), 1.0-2.0 weight percent of Mn, less than 0.015 weight percent of P (0 weight percent not included), less than 0.010 weight percent of S (0 weight percent not included); 0.005-0.060 weight percent of Al, 0.008-0.030 weight percent of Ti; 0.0020-0.010 weight percent of N, and less than 0.010 weight percent of O (0 weight percent not included). The microscopic constitution at the t/4 position of the steel board comprises mixed constitution of ferrite and bainite, wherein t represents thickness of the steel board. Island martensite is dispersed in the bainite, the average particle diameter of the ferrite is 10-50 mu m, and the island martesite in the bainite is 1-20 area percent of the total area.

The invention discloses a high-surface-quality hot-galvanized transformation induced plasticity (TRIP) steel plate and a manufacturing method thereof. The hot-galvanized TRIP steel plate is prepared from chemical components in percentage by weight as follows: 0.10%-0.15% of C, 1.20%-1.80% of Mn, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 1.20%-2.40% of Als and the balance of Fe and inevitable impurities. The manufacturing method of the TRIP steel plate comprises the steps as follows: continuous casting steelmaking-hot rolling-cold rolling-continuous annealing and hot galvanizing. The structure form of the hot-galvanized TRIP steel plate prepared with the method includes ferrite, bainite, retained austenite and martensite, the grain size grade ranges from Grade 10.5 to Grade 11, the tensile strength ranges from 640 MPa to 670 MPa, the yield strength ranges from 395 MPa to 465 MPa, the ductility is higher than or equal to 30%, the strength and ductility product can be 23GPa% or above, and the plate has the high surface quality, mechanical performance and corrosion resistance.

Provided are a wire rod, etc. for which spheroidize annealing and quenching/tempering heat treatment steps can be omitted. The wire rod has a specified chemical composition. In area ratio, at least 90% of the metal structure is bainite. The average bainite block grain diameter in the surface layer measured in a transverse cross-section is 15 Mum or less. The ratio between the average bainite blockgrain diameter in the surface layer measured in a transverse cross-section and the average bainite block grain diameter measured in the center section is less than 1.0, and the average grain diameterof cementite dispersed in the bainite is 0.1 Mum or less.