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Control method of central segregation of φ280mm 30crmo round tube billet

A control method and a round tube billet technology, which is applied in the field of iron and steel metallurgy, can solve problems such as center segregation of 30CrMo round tube steel billets, and achieve the effects of reducing center segregation, improving purity, and increasing the nucleation rate of equiaxed crystals

Active Publication Date: 2017-11-03
PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the shortcomings such as center segregation easily occurring in existing 30CrMo round tubular steel billets with larger cross-sectional dimensions, the technical problem to be solved by the present invention is to provide a method for controlling center segregation of 30CrMo round tubular steel billets with a section of φ280mm

Method used

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Examples

Experimental program
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Effect test

Embodiment

[0025] A steelmaking plant adopts 120t converter smelting→LF furnace refining→RH refining→six-machine and six-strand casting machine to produce 30CrMo round tube billets with a section of φ280mm. At the end of converter blowing, the end point carbon is controlled at 0.05%, the end point phosphorus is 0.006%, and the end point temperature is controlled at 1675°C.

[0026] When the molten steel arrives at the LF refining furnace, the molten steel fluctuates slightly for argon blowing, and there is no major overturning phenomenon. The outbound Alt is controlled at a mass percentage of 0.040%. After refining, the molten steel is weakly blown with argon. After the treatment, the temperature was set at 1490°C.

[0027] Then carry out RH refining. After the molten steel arrives at the station, the RH refining argon blowing flow rate is controlled at 1450NL / min, the processing time is 11min when the vacuum degree is less than 3mbar, and the Alt of the RH outbound station is 0.030%. T...

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Abstract

The invention discloses a center segregation control method for producing a 30CrMo circular tube steel casting blank with the cross section of phi280mm, belonging to the field of metallurgy. The method comprises the following steps: converter smelting, LF (ladle furnace) refining of molten steel, RH refining, continuous casting of molten steel and the like. The key technology is characterized in that a crystallizer electromagnetic stirring-final electromagnetic stirring combined technique is adopted in the continuous casting stage. The reasonable parameter control is performed in the molten steel smelting stage to enhance the purity of molten steel and achieve the optimal outbound conditions; in the molten steel casting process, the crystallizer electromagnetic stirring-final electromagnetic stirring combined mode is adopted, so that the molten steel components are uniformized; the casting is carried out at lower temperature, so that the blank shell grows uniformly; and thus, the columnar crystal structure is continuously eroded and blown out in the stirring process, the equiaxed grain nucleation rate is enhanced, and the columnar crystal growth is inhibited, thereby avoiding or reducing the center segregation of the casting blank.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy, in particular to a central segregation control method for producing 30CrMo round tubular steel billets with a section of φ280mm. Background technique [0002] 30CrMo billet steel is mainly used for the production of steel for oil well pipes used in oil and gas exploitation and transportation. P≤0.020%, S≤0.010%, V≤0.015%, Cr: 0.85%~1.05%, Mo: 0.17%~0.24%, Cu≤0.15%, Ni≤0.20%, Alt: 0.020%~0.040%, Residual element requirements: Nb≤0.010%, Ti≤0.010%, B≤0.005%, and V+Nb+Ti+B+Zr≤0.15%; As≤0.015%, Sn≤0.010%, Sb≤0.010%, Pb≤0.008 %, Bi≤0.010%, and As+Sn+Sb+Pb+Bi≤0.045%, and the balance is Fe. Under the joint action of stress and hydrogen sulfide gas during use, brittle fracture (called hydrogen sulfide stress corrosion) will occur suddenly when the stress is much lower than its own yield strength, which will easily cause problems such as production leakage, which is harmful to production and ad...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C33/04C21C5/28C21C7/10C21C7/00B22D11/115B22D11/117
CPCB22D11/006B22D11/115B22D11/117C21C5/28C21C7/00C21C7/10C22C33/04
Inventor 陈亮陈天明李红光郭华李扬洲郭奠荣杨文中李志强冯远超
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP