Pass system and roughing process for avoiding cracks on surface of large-size round steel

A surface crack and large-scale technology, applied in the field of metallurgy, can solve problems such as surface cracks, achieve the effects of improving the formation probability, avoiding instability, and avoiding surface cracks

Active Publication Date: 2014-12-17
NANJING IRON & STEEL CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the defective of prior art, the purpose of the present invention is to provide a kind of pass structure and rough rolling process that avoids large-scale round steel surface crack, the present invention is by rationally selecting rough rolling mill rough rolling pass system and rolling process, thereby Solve the problem of surface cracks produced by rolling large rectangular continuous casting slabs to produce large-size round steel

Method used

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  • Pass system and roughing process for avoiding cracks on surface of large-size round steel

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Effect test

Embodiment 1

[0014] The finished product specification of 320mm×480mm rectangular billet is φ130mmSAE4137 large-size round steel. The rough rolling pass system is designed as follows: the pass system is composed of pass Ⅰ, pass Ⅱ and pass Ⅲ. Among them, the groove bottom width dimension b of pass type I and pass type II k The ratios to the width B of the incoming material entering the pass for the first time are 1.043 and 1.033, respectively. Groove bottom width dimension b of pass type III k The difference from the incoming width B is 1mm. Hole slot width B k Satisfies the relationship: B k =b+△. Where b is the maximum width of the rolled piece out of the pass. The widening allowances △ of the three pass types are 12mm, 5mm and 5mm respectively. Roll gap S=0.021×roll diameter D. Hole height h k =(notch width B k - groove bottom width b k ) / pass sidewall slope tanψ+roll gap S, where the values ​​of the three pass sidewall slopes tanψ are 26.7%, 18.0% and 13.3%, respectively. Gro...

Embodiment 2

[0016] The finished product specification of 320mm×480mm rectangular billet is φ150mm25MnCrNiMo large-size round steel. The rough rolling pass system is designed as follows: the pass system is composed of pass type Ⅰ, pass type Ⅱ and pass type Ⅲ. Among them, the groove bottom width dimension b of pass type I and pass type II k The ratios to the width B of the incoming material entering the pass for the first time are 1.043 and 1.033, respectively. Groove bottom width dimension b of pass type III k The difference from the incoming width B is 1mm. Hole slot width B k Satisfies the relationship: B k =b+△. Where b is the maximum width of the rolled piece out of the pass. The widening allowances △ of the three pass types are 12mm, 5mm and 5mm respectively. Roll gap S=0.021×roll diameter D. Hole height h k =(notch width B k - groove bottom width b k ) / pass sidewall slope tanψ+roll gap S, where the values ​​of the three pass sidewall slopes tanψ are 26.7%, 18.0% and 13.3%, ...

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Abstract

The invention discloses a pass system and a roughing process for avoiding cracks on the surface of large-size round steel. The bottom width size b(i)k( / i) of a channel for roughing a first pass to the (n-1)th pass and the width B of an incoming material entering the passes at the first time meet the following relation that b(i)k( / i) / B is equal to 1.030-1.045; the bottom width size b(i)k( / i) of a channel for roughing the nth pass and the width B of the incoming material meets the following relation that B minus b(i)k( / i) is equal to 0-3mm; the width B(i)k(i) of the pass channel opening, a maximum value b of a rolled piece outputted from the pass and broadening allowance delta meet the following relation that the B(i)k(i) is equal to b plus delta; the start rolling temperature of the roughing process is controlled to be 1,100-1,200DEG C; the finish rolling temperature is controlled to be 1,000-1,100 DEG C. According to the pass system and the roughing process disclosed by the invention, rolling cracks on the surface of the large-size round steel are effectively eliminated, and the yield of products is remarkably improved.

Description

technical field [0001] The invention belongs to the field of metallurgy, and relates to a roll pass system, in particular to a pass system and a rough rolling process for avoiding cracks on the surface of hot-rolled round steel with a diameter of 100 to 180 when rolling a large rectangular continuous casting slab. Background technique [0002] Large-scale round steel with a diameter of φ100~φ180mm is widely used in automobiles, machinery, military industry, petroleum and other industries. At present, such large-size round steel is generally produced by single-stand multi-pass reversible rough rolling plus multi-stand hot continuous rolling with large rectangular billets. In order to facilitate the organization of production and improve the pass commonality, a set of pass system is often used for rough rolling of large-scale round steel with a diameter of φ100 ~ φ180mm. However, due to the large amount of rough rolling deformation and the unreasonable rolling temperature, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B1/16B21B37/74
Inventor 张龙李佑河黄贞益刘建唐鑫张晓云熊兵
Owner NANJING IRON & STEEL CO LTD
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