CN102766807A

CN102766807A - Boron contained bainite steel plate and manufacturing method thereof

Info

Publication number: CN102766807A
Application number: CN2012102683121A
Authority: CN
Inventors: 高志国; 李培德; 史文义; 康利明; 王海明; 张辉
Original assignee: Baotou Iron and Steel Group Co Ltd
Current assignee: Baotou Iron and Steel Group Co Ltd; Inner Mongolia Baotou Steel Union Co Ltd
Priority date: 2012-07-31
Filing date: 2012-07-31
Publication date: 2012-11-07

Abstract

A boron contained bainite steel plate and a manufacturing method of the boron contained bainite steel plate belong to the technical field of metallurgy, relate to molding technology, and are characterized in that a plate blank comprises (according to percentage) chemical compositions of 0.20%-0.35% of C, 1.5%-2.0% of Mn, 0.6%-1.6% of Si, no more than 0.015% of P, no more than 0.005% of S, 0.02-0.06% of Ti, 0.0005-0.0040% of B, no less than 0.02% of Alt, the balance of Fe and unavoidable impurities. The heating temperature of the plate blank is 1200-1250 DEG C, the heat preservation time is 1-6h, the start rolling temperature is 1000-1180 DEG C, the finish rolling temperature is 900-950 DEG C, the rolling cumulative reduction is larger than or equal to 50%, and the cooling rate is 2-10 DEG C/s. The thickness of a finished plate is 5-15mm. Products manufactured by using the process have excellent mechanical property, the tensile strength of 800-1300 MPa, the yield strength of 750-1000 MPa and the elongation coefficient of 13-21%.

Description

A kind of B bainitic steel plate and method of manufacture thereof of containing

Technical field

The invention discloses a kind of B bainitic steel plate and method of manufacture thereof of containing, belong to iron and steel novel material processing technique field, relate to microalloying and steel plate heat processing technique.

Background technology

As everyone knows, because low-carbon bainite steel has good toughness, welding property excellent characteristics, be applied to fields such as engineering machinery manufacturing, bridge, shipbuilding, vehicle manufacturing, petroleum transport pipe manufacturer.For appropriate design microalloying boron steel, obtain bainite structure, need combine with controlled rolling and technology for controlled cooling.Early stage boron steel mainly is quenching and the tempered steel with martensitic stucture, and boron helps improving martensite hardening capacity.Yet for low-carbon bainite steel, metallographic structure is main with bainite, particularly bainite hardening capacity.The alloying fundamental element that the theory and combining practice obtains bainite structure type low alloy steel is molybdenum and trace B.Add molybdenum element and can impel the perlitic transformation curve to move to right greatly effectively, separate out but can not suppress to analyse ferritic earlier fully.After adding the trace B element, boron gathers on austenite grain boundary partially, can effectively suppress proeutectoid ferrite and separate out, thereby improve bainite hardening capacity.Theoretical analysis thinks that the adding of boron can make the perlitic transformation curve move to right by a relatively large margin, and little to the bainite transformation influence.

The present invention discloses a kind of B bainitic steel plate and method of manufacture thereof of containing; Through adding the trace B element; Change the tissue of hot rolling attitude high tensile steel plate through the controlled rolling and controlled cooling technology; Make that the structural transformation of being made up of ferritic+perlite is a large amount of bainites+a small amount of pearlitic structure, its mechanical property is significantly improved.

Summary of the invention

The objective of the invention is to disclose a kind of B bainitic steel plate and method of manufacture thereof of containing, the chemical ingredients of its slab (weight percent) content should meet: C 0.20%-0.35%, Mn 1.5%-2.0%; Si 0.6%-1.6%, P≤0.015%, S≤0.005%; Ti 0.02%-0.06%; B 0.0005%-0.0040%, Alt>=0.02%, surplus is Fe and unavoidable impurities.

The Heating temperature of slab is 1200-1250 ℃, soaking time 1-6 hour, and adopt continous way rolling, start rolling temperature 1000-1180 ℃, finishing temperature 900-950 ℃, rolling total reduction >=50%, rate of cooling 2-10 ℃/s.

Production board thickness is 5-15mm.The product of explained hereafter has excellent mechanical property thus, tensile strength 800-1300MPa, ys 750-1000MPa, unit elongation 13-21%.

Outstanding advantage of the present invention is to make hot-rolled steel sheet not only have high-strength high-plasticity through controlled rolling and technology for controlled cooling adjustment, but also can obtain the bainite steel plate, and the production technique handiness is strong, can realize suitability for industrialized production.

Description of drawings

Fig. 1 is the typical gold phase constitution photo of embodiment 1 correspondence;

Fig. 2 is the typical gold phase constitution photo of embodiment 2 correspondences;

Embodiment

Below in conjunction with embodiment the present invention is done further detailed explanation.

Embodiment 1

Put into process furnace with intending rolling slab, (weight percent) chemical ingredients of slab is: C 0.25%, and Mn 1.76%, and Si 0.8%, and P 0.009%, and S 0.002%, and Ti 0.03%, and B 0.0013%, and Alt 0.027%, and surplus is Fe and unavoidable impurities.

Slab thickness is 95mm, 1220 ℃ of Heating temperatures, soaking time 1.5 hours.1140 ℃ of start rolling temperatures, 920 ℃ of finishing temperatures, rolling total reduction 75%, rate of cooling is 5 ℃/s.Its mechanical property detected value is seen table 1, and metallographic structure is as shown in Figure 1.

Table 1 mechanical property detected value

Project	R _m(MPa)	R _p0.2(MPa)	A?(%)	R _0.2/R _m	HB
						Embodiment 1	1115	905	17	0.81	367

Embodiment 2

Slab thickness is 95mm, 1220 ℃ of Heating temperatures, soaking time 1.5 hours.1140 ℃ of start rolling temperatures, 920 ℃ of finishing temperatures, rolling total reduction 75%, rate of cooling is 7 ℃/s.Its mechanical property detected value is seen table 2, and metallographic structure is as shown in Figure 2.

Table 2 mechanical property detected value

Project	R _m(MPa)	R _p0.2(MPa)	A?(%)	R _0.2/R _m	HB
						Embodiment 2	1250	950	15	0.76	413

Claims

1. one kind contains B bainitic steel plate and method of manufacture thereof, it is characterized in that chemical ingredients is by weight percentage: C 0.20%-0.35%, Mn 1.5%-2.0%; Si 0.6%-1.6%, P≤0.015%, S≤0.005%; Ti 0.02%-0.06%; B 0.0005%-0.0040%, Alt>=0.02%, surplus is Fe and unavoidable impurities.

2. a kind of method of manufacture that contains the B bainitic steel plate of characteristic according to claim 1; It is characterized in that Heating temperature is 1200-1250 ℃, soaking time 1-6 hour, adopt continous way rolling; Start rolling temperature 1000-1180 ℃; Finishing temperature 900-950 ℃, rolling total reduction >=50%, rate of cooling 2-10 ℃/s.