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High intensity, corrosion resistant and high ductility steel for mooring chain and production process thereof

A production process and corrosion-resistant technology, which is applied in the field of alloy steel, can solve problems such as high content of Ni in the composition, internal cracks in the material, and scrapped materials, and achieve the effects of good welding performance, improved strength and toughness, and energy saving

Inactive Publication Date: 2008-05-21
JIANGSU SHAGANG GROUP HUAIGANG SPECIAL STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the overall high setting of the alloy composition, the structure of the material is semi-martensitic, and the material must be annealed before delivery, otherwise the material will undergo martensitic transformation during placement, resulting in structural stress, resulting in material Internal cracks appear, once internal cracks occur, the material will be scrapped as a whole, and the Ni content in the composition is high, which not only increases the cost, but also causes a waste of resources

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Embodiment 1: adopt following production technology to prepare:

[0037] (1) Smelting: Add molten iron and steel scrap to a top-bottom double-blowing converter of more than 60 tons to realize pre-removal of P and initial adjustment of components;

[0038] (2) LF refining: Desulphurization, deoxygenation and composition fine-tuning in LF furnaces of more than 60 tons;

[0039] (3) RH / VD refining: use more than 60 tons of RH / VD refining to realize vacuum degassing, ensure [H]≤0.00015% and remove inclusions;

[0040] (4) Continuous casting: the R14m 6-machine 6-strand continuous casting machine produced by Italian Danieli Company is used to cast a round billet of φ380mm-500mm;

[0041] (5) Continuous rolling: use one billet stand and 6 continuous rolling units to roll into steel bars for mooring chains;

[0042] (6) Non-destructive flaw detection, using ultrasonic and eddy current flaw detection units to inspect the surface and internal quality of the bar.

[0043] The ...

Embodiment 2

[0048] C 0.24%, Si 0.20%, Mn 1.52%, Cr 1.10%, Ni 1.00%, Mo 0.58%, Nb 0.040%, Al 0.022%, S 0.0030%, P 0.010%, B 0.0003%, Cu 0.01%, Sb 0.002%, Sn 0.0015%, As 0.006%, [O] 0.0010%, [N] 0.0048%, the rest is Fe.

[0049] The φ150mm bar is sampled after overall quenching and tempering (900°C water quenching, 620°C water tempering), and the obtained mechanical properties are as follows:

[0050] Tensile strength R m =930MPa, yield strength R e1 =840MPa, Elongation A 5 =19%, reduction of area Z=66%, -20°C, V-notch impact energy AKv=145J.

[0051] All the other implementations are as in Example 1.

Embodiment 3

[0053] C 0.22%, Si 0.23%, Mn 1.50%, Cr 1.28%, Ni 0.80%, Mo 0.50%, Nb 0.030%, Al 0.026%, S 0.0040%, P 0.012%, B 0.0005%, Cu 0.01%, Sb 0.006%, Sn≤0.02%, As 0.005%, [O]≤0.0014%, [N]≤0.0046%, the rest is Fe.

[0054] The φ95mm bar is sampled after overall quenching and tempering (900°C water quenching, 620°C water tempering), and the obtained mechanical properties are as follows:

[0055] Tensile strength R m =910MPa, yield strength R e1 =745MPa, Elongation A 5 =25%, reduction of area Z=71%, -20°C, V-notch impact energy AKv=148J.

[0056] All the other implementations are as in Example 1.

[0057] After the mooring chain steel of the present invention is used by Zhengmao Group, the properties of the mooring chain products are as follows:

[0058] The chain-making process of the mooring chain is: use the flash preheating butt-welding special unit to weave and butt-weld the bar. After the chain is made, it needs to be tempered in a vertical continuous tempering furnace: quenchi...

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Abstract

The invention discloses a steel for mooring chains with high strength, corrosion resistance and high toughness and a production process thereof. Its chemical composition (wt%) is: C 0.18-0.25%, Si 0.10-0.35%, Mn 1.40-1.80%, Cr0.80-1.40%, Ni 0.60-1.20%, Mo 0.40-0.70%, Nb 0.02-0.06 %, Al0.02-0.06%, S≤0.010%, P≤0.020%, B≤0.005%, Cu≤0.20%, Sb≤0.010%, Sn≤0.03%, As≤0.04%, [O]≤0.0018% , [N]≤0.0060%, the rest is Fe. The present invention avoids the generation of martensitic structure through the composition optimization design, so that when the base metal does not adopt an annealing process, the material structure will not change and produce central cracks after a long time of storage, and the precious metal Ni is saved at the same time. The invention adopts RH / VD to degas and remove inclusions, which can significantly improve the cleanliness of steel, and reduce energy consumption and cost by adopting converter smelting.

Description

Technical field: [0001] The invention relates to alloy steel in the iron and steel industry, in particular to the design and production process of high-strength, corrosion-resistant and high-toughness steel for mooring chains. Background technique: [0002] With the development of modern industry, the development of marine resources is getting deeper and deeper. In particular, marine facilities such as deep-sea oil extraction, marine exploration, and national defense construction require the use of a large number of mooring chains. load, all put forward strict requirements on the overall performance of the mooring chain, not only require high strength and good toughness of the material, but also require the material to have good seawater corrosion resistance, fatigue resistance, wear resistance, good welding performance and low temperature of the weld joint Impact toughness. The diameter of the bars used to manufacture mooring chains is generally φ70mm-φ160mm, of which mor...

Claims

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Application Information

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IPC IPC(8): C22C38/48C22C38/58C22C33/04C21C7/00B22D11/16B21B37/16B21B1/46C21D8/06
Inventor 何达平王忠英尹修刚张小华王刚
Owner JIANGSU SHAGANG GROUP HUAIGANG SPECIAL STEEL CO LTD
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