400 MPa-grade Ti-containing hot-rolled ribbed steel bar and production process thereof

A hot-rolled ribbed steel bar and production process technology, applied in the field of threaded steel bar manufacturing, can solve the problems of not reaching HRB400 yield strength, increasing production difficulty, consumption of spare parts, and inability to pour steel smoothly, so as to improve the strength and cost of steel bars Low, low manufacturing cost effect

Active Publication Date: 2019-08-09
新余钢铁股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are design defects in the technical solution of the invention: 1. The composition design is too wide, and the upper limit of C 0.30% and Si 1.00% exceeds the current national standard for construction steel bars GB / T 1499.1-2017 "Hot Rolled Plain Steel Bar" C 0.25% , Si 0.55%, GB / T 1499.2-2018 "Hot-Rolled Ribbed Steel Bar" C 0.25%, Si 0.80% requirements, the embodiment 2 of the invention produces a ribbed steel bar with a diameter of 25mm C 0.29%, Si 0.98% composition exceeds the standard , is a waste product; while the 12mm diameter ribbed steel bar C 0.15%, Mn 0.61%, and Si 0.30% in Example 1 are low in composition, resulting in the yield strength R of the steel bar eL 324MPa, tensile strength R m It is 452MPa, which cannot reach the yield strength R of HRB400 eL ≥400MPa, tensile strength R m ≥540MPa requirements, also for waste
2. In steel, if Ti exceeds 0.030% and does not go into LF refining, it will cause Ti oxide bonding at the continuous casting nozzle, and the nozzle will be seriously blocked in the 1st to 3rd furnace, and the steel cannot be poured smoothly, which increases the difficulty of production and the consumption of spare parts

Method used

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  • 400 MPa-grade Ti-containing hot-rolled ribbed steel bar and production process thereof
  • 400 MPa-grade Ti-containing hot-rolled ribbed steel bar and production process thereof
  • 400 MPa-grade Ti-containing hot-rolled ribbed steel bar and production process thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051]Example 1: A 400MPa grade Ti-containing hot-rolled ribbed steel bar is smelted using a converter → tapping → argon blowing → adding ferrotitanium → continuous casting → heating → initial rolling → intermediate rolling → water precooling → finishing rolling → finishing Water cooling between rolling stands → first water cooling of the finished product → second water cooling of the finished product, rolling target diameter Φ12mm, including the following process steps:

[0052] (1) Converter smelting, argon blowing, continuous casting: Add molten iron and steel scrap into a 100-ton converter, top-bottom double-blowing smelting, oxygen blowing to remove C, blowing argon for 145s (seconds) during the steel discharge process, argon blowing pressure 0.80MPa, press System slag wash. Add silicomanganese, ferrosilicon, and silicon carbon balls in order when tapping 1 / 4 of the steel, deoxidize and alloy, transfer the ladle to the argon blowing station for alloy fine-tuning, and blow...

Embodiment 2

[0062] Example 2: A 400MPa-level Ti-containing hot-rolled ribbed steel bar is smelted using a converter → tapping → argon blowing → adding ferrotitanium → continuous casting → heating → initial rolling → intermediate rolling → water precooling → finishing rolling → finishing Water cooling between rolling stands → first water cooling of the finished product → second water cooling of the finished product, rolling target diameter Φ14mm, including the following process steps:

[0063] (1) Converter smelting, argon blowing, continuous casting: Add molten iron and steel scrap into a 100-ton converter, top-bottom double-blowing smelting, oxygen blowing to remove C, blowing argon for 140s (seconds) during the steel discharge process, argon blowing pressure 0.90MPa, press System slag wash. Add silicomanganese, ferrosilicon, and silicon carbon balls in order when tapping 1 / 4 of the steel, deoxidize and alloy, transfer the ladle to the argon blowing station for alloy fine-tuning, and blo...

Embodiment 3

[0072] Example 3: A 400MPa grade Ti-containing hot-rolled ribbed steel bar is smelted using a converter → tapping → argon blowing → adding ferrotitanium → continuous casting → heating → initial rolling → intermediate rolling → water precooling → finishing rolling → finishing Water cooling between rolling stands → first water cooling of the finished product → second water cooling of the finished product, rolling target diameter Φ16mm, including the following process steps:

[0073] (1) Converter smelting, argon blowing, continuous casting: Add molten iron and steel scrap into a 100-ton converter, top-bottom double-blowing smelting, oxygen blowing to remove C, blowing argon for 150s (seconds) during the steel discharge process, argon blowing pressure 0.75MPa, press System slag wash. Add silicomanganese, ferrosilicon, and carbon-silicon balls in order when tapping 1 / 4 of the steel, deoxidize and alloy, transfer the ladle to the argon blowing station for alloy fine-tuning, and blo...

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Abstract

The invention discloses a 400 MPa-grade Ti-containing hot-rolled ribbed steel bar and a production process thereof. The 400 MPa-grade Ti-containing hot-rolled ribbed steel bar comprises the followingchemical components of, 0.20%-0.25% of C, 0.55%-0.70% of Si, 1.40%-1.60% of Mn, smaller than or equal to 0.012% of N, smaller than or equal to 0.038% of P,smaller than or equal to 0.038% of S, 0.006%-0.012% of Ti, smaller than or equal to 30 ppm of O, and the balance Fe and inevitable impurities; and the matrix structure is ferrite and pearlite, the steel bar ReL is greater than or equal to 425 MPa, Rm isgreater than or equal to 590 mpa, A is greater than or equal to 25.0%, Agt is greater than or equal to 14.0%, R0m / R0eL is greater than or equal to 1.32, and R0eL / ReL is smaller than or equal to 1.15. According to the method, cheap elements C, Si and Mn are fully used to enhance the matrix, and then the micro-Ti and alternate low-cooling water-penetrating rolling process is used to refine the grain structure, the strength of the steel bar is further improved, the high-performance 400 MPa-grade Ti-containing hot-rolled ribbed steel bar which meets the standard requirement is obtained, and the manufacturing cost is low.

Description

technical field [0001] The invention relates to the technical field of threaded steel bar manufacturing, in particular to a 400MPa Ti-containing hot-rolled ribbed steel bar and a production process thereof. Background technique [0002] The national standard GB / T 1499.2-2018, which came into effect on November 1, 2018, has made different regulations on the macroscopic metallography, cross-sectional Vickers hardness, microstructure and inspection methods of hot-rolled ribbed steel bars. The new standard stipulates that the metallographic structure of hot-rolled ribbed steel bars is ferrite plus pearlite, and tempered martensite structure should not appear on the base circle, and the macroscopic metallographic structure does not allow the appearance of cross-sectional base circles that are obviously different from the inner area. The closed ring of contrast; for the non-closed ring that appears, the difference between the chilled layer at the edge of the base circle of the sec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/14C21D8/02
CPCC21D8/0226C21D2211/005C21D2211/009C22C38/001C22C38/002C22C38/02C22C38/04C22C38/14
Inventor 冯小明龚红根杨红来吴绍杰黄小山王海轮刘小林曾波王国文刘辉杰张春斌操瑞宏王学林肖侃简忠陈欢邹锦忠江先海夏雪生张全庆马小妹
Owner 新余钢铁股份有限公司
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