Hot-rolled wire rod for hardening-tempering-free hot galvanizing bolt and production technology of hot-rolled wire rod

A hot-rolled wire rod and production process technology, applied in metal rolling, temperature control, etc., can solve the problems of restricting the normal production of bolts, achieve the effects of easy control of the production process, reduce production costs, and shorten the incubation period

Active Publication Date: 2019-03-01
HANDAN IRON & STEEL GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With the increasingly stringent environmental protection requirements, the energy consumption and smoke pollution of the heat treatment process greatly limit the normal production of bolts. How to develop a product that can save the quenching and tempering process, meet the performance requirements of bolts, and have low cost, simple production process and easy for steel enterprises to stabilize. The production of hot-rolled wire rods for bolts has become an urgent problem in the industry

Method used

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  • Hot-rolled wire rod for hardening-tempering-free hot galvanizing bolt and production technology of hot-rolled wire rod
  • Hot-rolled wire rod for hardening-tempering-free hot galvanizing bolt and production technology of hot-rolled wire rod
  • Hot-rolled wire rod for hardening-tempering-free hot galvanizing bolt and production technology of hot-rolled wire rod

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Production of φ20mm hot-rolled wire rod, converter smelting molten steel, LF refining, RH refining, continuous casting into a square billet, the size is 150*150mm, the chemical composition of the billet is: C 0.30%, Si 0.40%, Mn 0.85%, P 0.025%, S0.008%, Cr 0.80%, the rest are iron and unavoidable impurity elements;

[0029] Heating the square billet to 1090°C and keeping it warm for 100 minutes, descaling the square billet with high-pressure water, the descaling high-pressure water pressure is not lower than 15MPa, after the surface is descaled, it undergoes rough rolling, intermediate rolling, finish rolling, and sizing in sequence. Among them, the temperature at the entrance of the final rolling is controlled at 760 ° C ~ 780 ° C;

[0030] Entering the Stelmore cooling line, the fan insulation cover and the fan are all closed.

[0031] For the φ20mm hot-rolled wire rod produced in Example 1, the inspection structure is basically ferrite+pearlite, and the tensile str...

Embodiment 2

[0033] Production of φ12mm hot-rolled wire rod, converter smelting molten steel, LF refining, RH refining, continuous casting into a square billet, the size is 150*150mm, the chemical composition of the billet is: C 0.40%, Si 0.15%, Mn 0.45%, P 0.011%, S0.025%, Cr 0.92%, the rest are iron and unavoidable impurity elements;

[0034] Heating the square steel billet to 1120°C and keeping it warm for 120min, descaling the surface of the square billet with high-pressure water, the water pressure is not lower than 15MPa, and going through rough rolling, intermediate rolling, finish rolling, reducing and sizing in sequence, and the final rolling temperature is controlled at 790°C ~810°C;

[0035] Entering the Stelmore cooling line, the fan insulation cover and the fan are all closed.

[0036] For the φ12mm hot-rolled wire rod produced in Example 2, the inspection structure is basically ferrite + pearlite, and the tensile strength is 660MPa-680MPa. After drawing, cold heading and que...

Embodiment 3

[0038] Production of φ16mm hot-rolled wire rod, converter smelting molten steel, LF refining, RH refining, continuous casting into a square billet, the size is 150*150mm, the chemical composition of the billet is: C 0.35%, Si 0.23%, Mn 0.56%, P 0.012%, S0.009%, Cr 1.10%, and the rest are iron and unavoidable impurity elements.

[0039]Heating the square billet to 1130°C and keeping it warm for 140 minutes; descaling the surface of the square billet with high pressure water, the pressure of the high pressure water is not lower than 15MPa, and then going through rough rolling, intermediate rolling, finish rolling, reducing and sizing in turn, after rolling, the final The rolling temperature is controlled at 800℃~820℃;

[0040] Entering the Stelmore cooling line, the fan insulation cover and the fan are all closed.

[0041] The φ16mm hot-rolled wire rod produced in Example 3 has a ferrite+pearlite inspection structure and a tensile strength of 655MPa to 685MPa. After drawing, co...

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Abstract

The invention discloses a hot-rolled wire rod for a hardening-tempering-free hot galvanizing bolt and a production technology of the hot-rolled wire rod. The wire rod is prepared from the following chemical components in percentage by mass: 0.30-0.40% of C, 0.15-0.35% of Si, 0.45-0.85% of Mn, less than or equal to 0.025% of P, less than or equal to 0.025% of S, 0.8-1.10% of Cr and the balance of iron and unavoidable impurity elements. In the production technology, after a continuous casting process is finished, a casting blank is heated to 1,090-1,130 DEG C, and the heat preservation is performed for 100-140 min; in a rolling process, the temperature at a finish rolling entrance is controlled at 760-830 DEG C; after the rolling, the process enters a Stelmor cooling line, and a fan heat cover and a fan are completely closed. According to the hot-rolled wire rod and the production technology disclosed by the invention, easy-to-deform ferrite and pearlitic structure are obtained through low-temperature rolling, thus the wire rod can be subjected to cold heading deformation without annealing; on the basis, by adding a proper amount of C, Si, Mn and Cr reinforcing elements, the bolt cansurely meet the requirements of 8.8-class hot galvanizing standard without hardening and tempering treatment; the bolt hardening and tempering treatment process of traditional technology is saved, the cost of deep processing is remarkably lowered, and the production efficiency is improved.

Description

technical field [0001] The invention relates to a hot-rolled wire rod and a production process thereof, in particular to a hot-rolled wire rod for 8.8-grade hot-dip galvanized bolts without quenching and tempering and a production process thereof. Background technique [0002] Quenching-free steel is a kind of green and environment-friendly steel, without quenching and high-temperature tempering process, the performance of steel after drawing and cold heading can reach the same level as quenched and tempered steel. Because heat treatment equipment and related production processes are omitted, energy consumption is reduced, and the cost of deep processing is reduced by 25-38% compared with quenched and tempered steel. The production of non-quenched and tempered steel is generally to add vanadium, titanium and niobium microalloying elements to the medium carbon manganese steel. During the cooling process, the microalloying elements vanadium, titanium and niobium form fine carb...

Claims

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Application Information

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IPC IPC(8): C22C38/18C22C38/04C22C38/02B21B1/46B21B37/74
CPCB21B1/463B21B37/74C22C38/002C22C38/02C22C38/04C22C38/18
Inventor 孙彩凤徐斌翟晓毅冯忠贤孙江波高建郗雄涛
Owner HANDAN IRON & STEEL GROUP
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