Q500-steel-grade low-alloy structural steel bar and controlled-rolling and controlled-cooling rolling method thereof

A controlled rolling, controlled cooling, and low alloy technology, applied in metal rolling and other directions, can solve the problems of high production costs, achieve the effects of improving yield strength and low temperature impact performance, achieving uniformity, and improving uniformity

Active Publication Date: 2022-02-18
DAYE SPECIAL STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problem of high production cost of Q500 steel grade materials in the prior art, the present invention provides a controlled rolling and controlled cold rolling method to effectively improve the strength and impact toughness of steel, so that low carbon equivalent low alloy structural steel can obtain high strength And low temperature impact toughness at the same time, greatly reduce the production cost

Method used

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  • Q500-steel-grade low-alloy structural steel bar and controlled-rolling and controlled-cooling rolling method thereof
  • Q500-steel-grade low-alloy structural steel bar and controlled-rolling and controlled-cooling rolling method thereof
  • Q500-steel-grade low-alloy structural steel bar and controlled-rolling and controlled-cooling rolling method thereof

Examples

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Effect test

Embodiment 1

[0056] This embodiment provides a controlled rolling and controlled cold rolling method for Q500 steel grade low-alloy structural steel bars, using a 390 mm steel billet round billet as a raw material to roll a finished product with a specification of 100 mm; the chemical composition of the steel billet (by mass percent, wt%) includes: C: 0.16; Si: 0.30; Mn: 1.40; P: 0.020; S: 0.008; Cr: 0.06; V: 0.06; Iron and unavoidable impurities, and CEV: 0.42.

[0057] The controlled rolling and controlled cold rolling method sequentially comprises the following steps: heating, rolling, spray cooling, KOCKS rolling, and cooling. Specific steps are as follows:

[0058] (1) Heating: Using a segmented heating process, the steel billet is placed in a heating furnace for heating. The preheating temperature is 680°C, the heating temperature of the first stage is 1030°C, the heating temperature of the second stage is 1130°C, and the soaking temperature is 1130°C.

[0059] (2) Rolling: Two-ro...

Embodiment 2

[0083] This embodiment provides a controlled rolling and controlled cold rolling method for Q500 steel grade low-alloy structural steel bars. The steel billet round billet with a specification of 390 mm is used as a raw material. The chemical composition of the billet (by mass percentage, wt%) includes : C: 0.11; Si: 0.35; Mn: 1.45; P: 0.018; S: 0.005; Cr: 0.18; V: 0.08; Al: 0.030; N: 0.0100; 0.404.

[0084]Using the same controlled rolling and controlled cold rolling method as in Example 1, the following steps are successively included: heating, rolling, spray cooling, KOCKS rolling, and cooling. The final bar specification is ∮100mm, and its properties are shown in Table 4. shown. It can be seen from Table 4 that the impact of the steel bar obtained by the present invention through controlled rolling and controlled cooling has reached more than 100J at -40°C, meeting the GB / T1591-2018 standard on Q500 steel grades (three grades of Q500MC, Q500MD and Q500ME) performance req...

Embodiment 3

[0087] This embodiment provides a controlled rolling and controlled cold rolling method for Q500 steel grade low-alloy structural steel bars, using a steel billet with a specification of 300 × 400mm as a raw material, and the chemical composition of the billet is the same as that of the billet in Example 1. The chemical composition is the same.

[0088] The controlled rolling and controlled cold rolling method comprises the following steps in sequence: heating, rolling, spray cooling, KOCKS rolling, and cooling to obtain a finished rolled material with a specification (diameter) of 50 mm. Specific steps are as follows:

[0089] (1) Heating: Using a segmented heating process, the steel billet is placed in a heating furnace for heating. The preheating temperature is 650°C, the heating temperature of the first stage is 1080°C, the heating temperature of the second stage is 1180°C, and the soaking temperature is 1180°C.

[0090] (2) Rolling: Two-roll rolling is adopted, the roll...

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Abstract

The invention discloses a Q500-steel-grade low-alloy structural steel bar and a controlled-rolling and controlled-cooling rolling method thereof, the Q500-steel-grade low-alloy structural steel bar comprises the following chemical components by weight percentage: 0.05%-0.18% of C, 0.20%-0.40% of Si, 1.00%-1.60% of Mn, less than or equal to 0.030% of P, less than or equal to 0.030% of S, less than or equal to 0.20% of Cr, less than or equal to 0.20% of Ni, less than or equal to 0.10% of Mo, less than or equal to 0.15% of Cu, 0.02-0.10% of V, less than or equal to 0.05% of Nb, less than or equal to 0.02% of Ti, less than or equal to 0.004% of B, 0.005-0.012% of N, 0.02-0.04% of Al and less than or equal to 0.45% of CEV=C+Mn / 6+(Cr+Mo+V) / 5+(Ni+Cu) / 15. According to the method, the initial rolling temperature of rolling ranges from 1000DEG C to 1050DEG C; by adopting the method, the uniformity of rolled piece structure can be realized.

Description

technical field [0001] The invention relates to a Q500 steel grade low-alloy structural steel bar and a rolling method thereof, belonging to the field of controlled rolling and controlled cooling of steel rolling. Background technique [0002] Q500 steel is a kind of bridge steel. With the application of high-strength bridge steel, brittle fracture accidents of steel structures have occurred frequently, and the economic losses and casualties caused by them have become more and more serious. At the same time, high-strength bridge steel cannot meet the design requirements of modern bridges in terms of toughness and other mechanical properties, which largely restricts its large-scale promotion and use in bridges. [0003] At present, in order to ensure that the strength of Q500 steel grade materials meets the requirements, a large amount of alloys such as Ni and Mo are generally added to the composition design, or Nb, V, Ti and other fine grain elements are added in combinatio...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/20C22C38/22C22C38/24C22C38/26C22C38/28C22C38/32C22C38/38C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/54C22C38/58B21B1/16C21D8/06
CPCC22C38/02C22C38/04C22C38/38C22C38/58C22C38/22C22C38/20C22C38/24C22C38/26C22C38/28C22C38/32C22C38/001C22C38/06C22C38/44C22C38/42C22C38/46C22C38/48C22C38/50C22C38/54C21D8/065B21B1/16C21D2211/009C21D2211/005Y02P70/10
Inventor 郭士北汪洋彭峰王占忠张越马建祎杜正龙陈君
Owner DAYE SPECIAL STEEL CO LTD
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