Base metal wire rod special for 1,420 MPa-level PC steel bar and preparation method of base metal wire rod

A wire rod and base metal technology, applied in the field of steel rolling, can solve the problems of delayed fracture, long heating time, residual stress of quenching cracking, etc.

Active Publication Date: 2020-07-07
WUKUN STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, some components are unreasonably designed. When downstream users make PC steel rods, the induction heating time is longer and the process of rapid quenching and low temperature tempering is required

Method used

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  • Base metal wire rod special for 1,420 MPa-level PC steel bar and preparation method of base metal wire rod
  • Base metal wire rod special for 1,420 MPa-level PC steel bar and preparation method of base metal wire rod
  • Base metal wire rod special for 1,420 MPa-level PC steel bar and preparation method of base metal wire rod

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preparation example Construction

[0023] The preparation method of the base metal wire rod for 1420MPa grade PC steel bar of the present invention comprises heating, rough rolling and pre-finish rolling, pre-controlled cooling, finish rolling, controlled cooling, silk spinning and slow cooling process, specifically comprising the following steps:

[0024] A. Heating: Send the billet into the heating furnace and heat it to 1040-1070°C. The billet includes the following chemical components in terms of mass percentage: C: 0.27%-0.32%, Si: 0.80%-1.00%, Mn: 1.0% ~1.20%, Ti:0.010~0.017%, P≤0.025%, S≤0.025%, Mo≤0.010%, N:≤0.0060%; and Si+Mn≤2.0%, Si:N≥160; the rest are Fe and unavoidable impurities;

[0025] B. Rough intermediate rolling and pre-finishing rolling: the heated billet is rolled for 18 passes, the starting rolling temperature is 1040-1070°C, and the total rolling reduction is 98.0%-98.6%;

[0026] C. Pre-cooling: Cool the rolled piece after leaving the pre-finishing unit in two stages, and carry out bac...

Embodiment 1

[0037] A cold billet of 150mm×150mm is fed into a heating furnace for heating. The billet contains the following chemical components in mass percentage: C: 0.30%, Si: 0.80%, Mn: 1.18%, Ti: 0.010%, P: 0.013%, S:0.019%, Mo:0.008%, N:0.0045%, Si+Mn=21.98%, Si:N=177; the rest is Fe and unavoidable impurities; The time is 60 minutes, and the steel billet after being released from the furnace is subjected to 18 passes of finish rolling and pre-finish rolling, with a total reduction rate of 98.6%, and a rolling start temperature of 1040°C, to obtain a pre-finish rolling piece. The rolled piece after pre-finish rolling is cooled by water in 2 stages, with a total water volume of 216m 3 / h, the ratio of water is 1.0:1.0, back-purging is carried out after inter-stage water cooling, and a 940°C rolling stock is obtained. The 940°C finishing rolling piece is then subjected to 6 passes of finishing rolling by the finishing rolling unit, and the total reduction rate of finishing rolling is...

Embodiment 2

[0040] Send a 150mm×150mm cold billet into a heating furnace for heating. The chemical composition of the billet is calculated by mass percentage: C: 0.27%, Si: 0.99%, Mn: 1.01%, Ti: 0.015%, P: 0.016% , S:0.020%, Mo:0.005%, N:0.0060%, Si+Mn=2.0%, Si:N=165; the rest is Fe and unavoidable impurities. The steel billet stays in the soaking section for 35 minutes, and the total time in the furnace is 80 minutes. The steel billet after being released from the furnace is subjected to 18 passes of finish rolling and pre-finish rolling. Rolled pieces. The rolled piece after pre-finish rolling is cooled by water in 2 stages, with a total water volume of 216m 3 / h, the ratio of water is 1:1, back-purging is carried out after inter-stage water cooling, and a 970°C rolling stock is obtained. The 970°C finishing rolling piece is then subjected to 6 passes of finishing rolling by the finishing rolling unit, and the total reduction rate of finishing rolling is 70%. The rolled piece after f...

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Abstract

The invention discloses a base metal wire rod special for a 1,420 MPa-level PC steel bar and a preparation method of the base metal wire rod. The base metal wire rod is prepared from following chemical components in percent by mass including 0.27%-0.32% of C, 0.80%-1.00% of Si, 1.0%-1.20% of Mn, 0.010%-0.017% of Ti, smaller than or equal to 0.025% of P, smaller than or equal to 0.025% of S, smaller than or equal to 0.010% of Mo, smaller than or equal to 0.0060% of N, smaller than or equal to 2.0% of Si+Mn, larger than or equal to 160 of Si:N and the balance Fe and inevitable impurities. The preparation method of the base metal wire rod includes the procedures of heating, rough intermediate rolling, pre-finish rolling, precontrol cooling, finish rolling, control cooling, spinning and slow cooling. Through optimization design of the steel components and coupling control of the steel rolling process, the rolling starting temperature, the finish rolling entering temperature and the spinning temperature of steel are properly increased, slow cooling is adopted after rolling is completed, thus, the residual stress and the quantity of saturated N and C gap atoms of the rolled base metal wire rod special for the PC steel bar are reduced, the natural aging time is shortened, the aging comprehensive performance is improved, the requirements for manufacturing the PC steel bar by downstreamusers are met, and the quality accidents such as drawing breakage, quenching cracks, lag breakage and upset head cracking are avoided.

Description

technical field [0001] The invention belongs to the technical field of steel rolling, and in particular relates to a special base material wire rod for 1420MPa grade PC steel bars and a preparation method thereof. Background technique [0002] PC steel rods (steel rods for prestressed concrete) have the advantages of high strength and toughness, low relaxation, and material saving, and are widely used in prestressed components such as pipe piles, viaduct piers, railway sleepers, and electric poles. With the rapid development of highways, bridges, high-rise and super high-rise buildings in China, the domestic market demand for PC steel rods has grown rapidly, and the demand for base metal wire rods for 1420MPa PC steel rods is relatively large. However, the base metal wire rod for 1420MPa grade PC steel bars is a high-strength alloy steel, and low-temperature rolling and rapid cooling are generally used for production to ensure strength. Due to low-temperature rolling and ra...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/12C22C38/14C21D8/08
CPCC21D8/065C21D8/08C21D2211/005C22C38/001C22C38/002C22C38/02C22C38/04C22C38/12C22C38/14
Inventor 张红斌陈伟张卫强李晓云王卫东张森赵亮王文峰马松文玉兵苏灿东
Owner WUKUN STEEL
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