CN102337456A

CN102337456A - Thick bridge steel plate and rolling method thereof

Info

Publication number: CN102337456A
Application number: CN201110291222XA
Authority: CN
Inventors: 董瑞峰; 高志国; 李文艺; 温利军; 张军; 刘哲; 李�浩; 乔继强; 岳祎楠; 高志慧
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: 2011-09-30
Filing date: 2011-09-30
Publication date: 2012-02-01

Abstract

The invention discloses a thick bridge steel plate and a rolling method, belonging to the technical field of metallurgy and relating to a forming technique. Chemical compositions and contents (in percentage by weight) of one plate blank of the thick bridge steel plate are as follows: 0.05-0.10% of C, 1.1-1.5% of Mn, 0.25-0.45% of Si, not more than 0.018% of P, not more than 0.010% of S, 0.020-0.055% of Nb, 0.020-0.060% of V, 0.006-0.025% of Ti and the balance of Fe and unavoidable impurities. The rolling method is as follows: the heating temperature is 1200-1250 DEG C; the temperature keeping time is 3-5 hours; the rough rolling opening temperature is 1180-1230 DEG C; the finish rolling opening temperature is 890-920 DEG C; the finished rolling temperature is 850-900 DEG C; the Acc final cooling temperature is 540-600 DEG C; the cooling speed is 5-12 DEG C/s; the tensile strength is not less than 530 MPa; the yield strength is not less than 400 MPa; the elongation is not less than 22%; and the Z-direction property is over 40%. The impact work under the condition of -40 DEG C is more than 200 J, and the ageing impact work under the condition of -40 DEG C is more than 170 J. The thick bridge steel plate disclosed by the invention has the characteristics of excellent mechanical property and low production cost; and the rolling method disclosed by the invention is suitable for producing steel plates with the thickness of 60-100 mm.

Description

A kind of thick specification bridge steel plate and rolling method thereof

Technical field

The invention discloses a kind of thick specification bridge steel plate and rolling method thereof, belong to field shaping technique, particularly hot-rolled steel plate technology.

Background technology

At present, thick specification bridge steel plate manufacturer is studied to the following thickness of 60mm, obtains high tensile hot rolled steel sheet through controlled chilling temperature and speed of cooling.Chinese patent (number of patent application 201010592034.6) like Ma'anshan Iron and Steel Co., Ltd's application discloses " preparation method of 420MPa H.T. Weather-resistance bridge steel and hot-rolled sheet coil thereof ", produces thickness and is 13.5-15.5mm resistant low alloy corrosion hot rolled coil.The Chinese patent (number of patent application 201010208305.3) of the research and development of the above thickness bridge steel plate of 100mm such as Nanyang Hanye Special Steel Co., Ltd.'s application discloses " Q345q special thick bridge steel plate of series and working method thereof "; Successfully develop special thick Q345qD (E) steel plate of 130mm through TMCP technology and thermal treatment, Z in kind reaches the Z15 level to performance." Wugang bridge plate Q370qD/Z25 production practice " literary composition (" Wide and Thick Slab " 2005; 11 (1): having reported P25-28) and can produce the bridge steel plate of the above thickness specification of 50mm through normalizing process, is that the thick specification of 60-100mm does not see have document, publication or patent gazette to publish or publish, report as yet with the Q370qE bridge steel plate of TMCP explained hereafter to thickness.The present invention discloses a kind of thick specification Q370qE bridge steel plate of employing TMCP explained hereafter and rolling method thereof, and it is blank to have filled up thick specification bridge steel plate research and development.

Summary of the invention

The objective of the invention is to disclose a kind of thick specification bridge steel plate and rolling method thereof, (weight percent) chemical composition content of its slab should meet: C 0.05%-0.10%, Mn 1.1%-1.5%; Si 0.25%-0.45%, P≤0.018%, S≤0.010%; Nb 0.020%-0.055%; V 0.020%-0.060%, Ti0.006%-0.025%, surplus is Fe and unavoidable impurities.

The rolling technology system of steel plate is: Heating temperature is 1200-1250 ℃, soaking time 3-5 hour, and 1180-1230 ℃ of roughing start rolling temperature, 890-920 ℃ of finish rolling start rolling temperature, finishing temperature 850-900 ℃.540-600 ℃ of Acc final cooling temperature, speed of cooling 5-12 ℃/s.

The outstanding advantage of the present invention is to adopt TMCP technology can produce the steel plate of the thick specification of thickness 60-100mm and have excellent mechanical property, and tensile strength >=530MPa, ys >=400MPa, unit elongation >=22%, Z are to performance more than 40%.-40 ℃ of ballistic works are greater than 200J, and-40 ℃ of timeliness ballistic works are greater than 170J.Carbon equivalent belongs to low welding crack sensitivity steel smaller or equal to 0.4%.

Description of drawings

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

Embodiment

Put into process furnace with intending rolling slab, (weight percent) chemical ingredients of slab is: C 0.067%, and Mn 1.39%; Si 0.42%, and P 0.010%, and S 0.002%; Nb 0.038%, and V 0.054%, and Ti 0.008%; Surplus is Fe and unavoidable impurities, and steel plate thickness is 70-90mm; Rolling technology is seen table 1, and its mechanical property detected value is seen table 2.Metallographic structure is formed (as shown in Figure 1) by perlite and ferritic, and grain fineness number reaches 10 grades.

Table 1 rolling technology

Table 2 mechanical property detected value

Claims

1. thick specification bridge steel plate is characterized in that chemical ingredients and content are by weight percentage: C 0.05%-0.10%, Mn 1.1%-1.5%; Si 0.25%-0.45%, P≤0.018%, S≤0.010%; Nb0.020%-0.055%, V 0.020%-0.060%, Ti 0.006%-0.025%; Surplus is Fe and unavoidable impurities, and steel plate thickness is 60-100mm.

2. a kind of thick specification bridge steel plate as claimed in claim 1 is characterized in that tensile strength >=530MPa, ys >=400MPa; Unit elongation >=22%; More than 40%, ballistic work is greater than 200J under-40 ℃ of conditions to performance for Z, and the timeliness ballistic work is greater than 170J under-40 ℃ of conditions.Carbon equivalent belongs to low welding crack sensitivity steel smaller or equal to 0.4%.

3. the rolling method of a thick specification bridge steel plate is characterized in that steel plate has chemical ingredients as claimed in claim 1, and its rolling technology is following: Heating temperature is 1200-1250 ℃; Soaking time 3-5 hour; 1180-1230 ℃ of roughing start rolling temperature, 890-920 ℃ of finish rolling start rolling temperature, finishing temperature 850-900 ℃; 540-600 ℃ of Acc final cooling temperature, speed of cooling 5-12 ℃/s.