Alloy reduced ship plate steel with yield strength of 355MPa and preparation process thereof

A technology of yield strength and preparation process, which is applied in the field of alloy reduced-weight ship plate steel with a yield strength of 355MPa and its preparation process, can solve the problems of complex production process and high alloy cost, and achieve high efficiency, low production cost and cheap chemical composition Effect

Inactive Publication Date: 2011-09-28
INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

High alloy cost and complex production process

Method used

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  • Alloy reduced ship plate steel with yield strength of 355MPa and preparation process thereof
  • Alloy reduced ship plate steel with yield strength of 355MPa and preparation process thereof
  • Alloy reduced ship plate steel with yield strength of 355MPa and preparation process thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] In Example 1, a 220 mm thick industrially produced continuous casting slab was used, and the size of the cut test slab was 220 (T) mm×140 (W) mm×250 (L) mm. of the test blank. The slab is produced through hot metal desulfurization→converter→LF→slab continuous casting machine.

[0034] Table 1 Chemical composition of experimental steel

[0035]

[0036] In this embodiment, a two-stage controlled rolling and controlled cooling (TMCP) experiment was carried out on a 750 mm two-roll reversing rolling mill with a rolling speed of 1.1 m / s. The final thickness (t) of the product is 20 mm. The rolling reduction procedure is as follows: 220→190→165→140→120→100→85→70→58→48→40→31→24→20 (mm).

[0037] Specifically, the process of this embodiment is as follows: the billet is heated to 1180°C and held for 2 hours; FR ), finish rolling to the target thickness (t) at different reduction ratios (FR); after finishing rolling, the rolled piece enters the laminar flow cooling device...

Embodiment 2

[0042] In Example 2, a 220 mm thick industrially produced continuous casting slab was used, and the size of the cut test slab was 220 (T) mm×140 (W) mm×250 (L) mm. The chemical composition (mass fraction) is shown in Table 3. The slab is produced by hot metal desulfurization→converter→LF→RH vacuum degassing-slab continuous casting machine.

[0043] Table 3 Chemical composition of experimental steel

[0044]

[0045] A two-stage controlled rolling and controlled cooling (TMCP) experiment was carried out on a 750mm two-roll reversing mill with a rolling speed of 1.1m / s. The final thickness (t) of the product is 20 mm. The rolling reduction procedure is as follows: 220→190→165→140→120→100→85→70→58→48→40→31→24→20 (mm).

[0046] Specifically, the process of this embodiment is as follows: the billet is heated to 1180°C and held for 2 hours; FR ), finish rolling to the target thickness (t) at different reduction ratios (FR); after finishing rolling, the rolled piece enters the...

Embodiment 3

[0050] In Example 3, the continuous casting slab size is 220×2265×3200-4200 (mm), and the chemical composition of the test steel is listed in Table 5. The continuous casting slab is soaked at 1200°C, and rolled into one 34mm and five 28mm wide and thick steel plates with a width of 2700-4100mm by using an industrial 5m wide and thick plate rolling mill and MULPIC controlled rolling and controlled cooling (TMCP). Test the tensile properties in the transverse direction (TD), and test the Charpy impact energy (KV2) in the longitudinal direction at -20°C. The TMCP process parameters and the mechanical properties of the steel plate are shown in Table 6 (a total of six samples, batch numbers A1305003, A1305004, A1305003, A1305006, A1305008, A1305009).

[0051] Table 5 Chemical composition of industrial test steel

[0052]

[0053]

[0054] Table 6 TMCP industrial test process parameters and mechanical properties of steel plates

[0055]

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Abstract

The invention provides an alloy reduced ship plate steel with yield strength of 355MPa and a preparation process thereof. The ship plate steel comprises the following components in percentage by weight: 0.13 to 0.18 percent of C, 0.10 to 0.35 percent of Si, 0.90 to 1.30 percent of Mn, 0.01 to 0.022 percent of Nb, 0.009 to 0.02 percent of Ti, 0.01 to 0.04 percent of Al, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S and the balance of Fe and impurities. The preparation process comprises: subjecting a continuously cast blank having the same components as the ship plate steel to heating, temperature preservation, hot rolling and cooling to form finished ship plate steel directly; and delivering in a thermo-mechanical control process (TMCP) state. The yield strength of the ship plate steel is over 355MPa, the low-temperature (-20 DEG C) impact toughness is high, and the maximum thickness is 40 millimeters. The alloy reduced ship plate steel is applicable to ship and ocean petroleum platforms, particularly manufacturing process of ship plates with high requirements on strength and low-temperature toughness and a requirement on high welding performance.

Description

technical field [0001] The invention particularly relates to an alloy weight-reducing ship plate steel with excellent low-temperature toughness and a yield strength level of 355 MPa and a preparation process thereof. Background technique [0002] The steel plate with a yield strength of 355MPa is one of the main materials required for ship construction, with a large output and a wide range of uses. On the basis of C-Mn steel, each steel factory adopts different microalloying, such as adding V, Nb, compound Nb-V and compound Nb-Ti in the steel to weld DH36 steel. This type of steel generally adopts two-stage controlled rolling (rough rolling, warming, finishing rolling) and rapid cooling (TMCP) process to produce DH36 steel plate. For Nb-containing steel, the finishing rolling temperature is 830-930°C; for V-containing steel, the finish-rolling starting temperature does not exceed 880°C; the thickness to be heated is 2 to 3.5 times the thickness (t) of the finished product. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/14B21B37/74
Inventor 刘东升朱浩皱志文
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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