High-grade large-strain pipeline steel and manufacturing method of steel pipe

A manufacturing method and technology of pipeline steel, applied in the direction of pipes/pipe joints/fittings, pipes, rigid pipes, etc., can solve the influence of safety in use, limit the deformation capacity of pipeline steel and steel pipe, and can not take into account the strain aging performance, etc. problem, to achieve the effect of good plastic deformation capacity, good toughness and weldability, low strain aging sensitivity

Active Publication Date: 2010-12-08
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, with the development of controlled rolling air-cooling technology, the yield ratio of pipeline steel has risen from 0.80 to 0.85 in the past to 0.90 to 0.95. Too high yield ratio limits the deformation capacity of pipeline steel and ste

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0013] Example 1:

[0014] Alloy composition: C: 0.04%; Mn: 1.74%; Si: 0.18%; P: 0.009%; S: 0.003%; Al: 0.01%; Ca: 0.003%; N: 0.005%; Nb: 0.05%; Ti: 0.02%; Mo: 0.18%; Ni: 0.19%; Cu: 0.16%; the balance is Fe and inevitable impurities; the cold crack sensitivity coefficient is 0.16%, and the carbon equivalent is 0.39%.

[0015] Manufacturing process: The above-mentioned materials are smelted in an oxygen blowing converter, treated with Ca, refined outside the furnace and vacuum degassed, continuously cast into slabs, heated to about 1200°C, rough rolled at 1000°C to 1100°C, finish rolled at 650°C to 900°C, The cooling rate after rolling is 20°C-30°C / s, and a hot-rolled steel sheet with a thickness of about 18.4mm is produced. The steel plate is then formed by JCO, using multi-pass longitudinal submerged arc welding. The welding material is a fine-grained acicular ferrite material with low oxygen content containing Ti-B, and then the diameter is expanded by 0.6 to 0.8% to form a long...

Example Embodiment

[0017] Example 2

[0018] Alloy composition: C: 0.08%; Mn: 1.53%; Si: 0.23%; P: 0.008%; S: 0.002%; Al: 0.018%; Ca: 0.002%; N: 0.004%; V: 0.04%; Ti: 0.03%; Mo: 0.24%; Ni: 0.25%; Cr: 0.19%; the balance is Fe and inevitable impurities; the cold crack sensitivity coefficient is 0.20%, and the carbon equivalent is 0.45%.

[0019] Manufacturing process: The above-mentioned materials are smelted in an oxygen blowing converter, treated with Ca, refined outside the furnace and vacuum degassed, continuously cast into slabs, heated to about 1200°C, rough rolled at 1000°C to 1100°C, finish rolled at 680°C to 930°C, After rolling, the cooling rate is 25°C-35°C / s, and the hot-rolled steel sheet is made into a thickness of about 22mm. The steel plate is then formed by JCO, using multi-pass longitudinal submerged arc welding, and the welding material is a fine-grained acicular ferrite material with low oxygen content containing Ti-B, and then the diameter is expanded by 0.7-0.9% to form a straigh...

Example Embodiment

[0021] Example 3:

[0022] Alloy composition: C: 0.06%; Mn: 1.87%; Si: 0.27%; P: 0.007%; S: 0.003%; Al: 0.03%; Ca: 0.003%; N: 0.003%; Nb: 0.04%; Ti: 0.02%; Mo: 0.28%; Ni: 0.30%; Cu: 0.27%; Cr: 0.29%; B: 0.004%, Re: 0.05%, the balance is Fe and inevitable impurities; cold crack sensitivity coefficient 0.23%, The carbon equivalent is 0.53%.

[0023] Manufacturing process: The above-mentioned materials are smelted in an oxygen blowing converter, treated with Ca, refined outside the furnace and vacuum degassed, and continuously cast into slabs, heated to about 1200°C, rough rolled at 1000°C to 1100°C, and finish rolled at 700°C to 950°C. After rolling, the cooling rate is 25°C-35°C / s, and it is tempered at 200-300°C online to make a hot-rolled steel sheet with a thickness of about 26.2mm. The steel plate is then formed by JCO, and longitudinal submerged arc welding. The welding material is made of Ti-B-containing fine-grained acicular ferrite material with low oxygen content, and the...

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Abstract

The invention relates to a high-grade large-strain pipeline steel and a manufacturing method of a steel pipe. The high-grade large-strain pipeline steel comprises the following components in percentage by mass: 0.04-0.08 percent of C, 1.50-1.90 percent of Mn, 0.15-0.30 percent of Si, not more than 0.010 percent of P, not more than 0.003 percent of S, 0.005-0.03 percent of Al, 0.002-0.005 percent of Ca, not more than 0.005 percent of N, and the balance of Fe, wherein the carbon equivalent is not more than 0.55 percent and cold cracking sensitivity coefficient is not more than 0.25. The manufacturing method comprises the following steps of: carrying out smelting, Ca treatment, refining and degassing on the pipeline steel; carrying out continuous casting on the pipeline steel to form a thick plate blank; carrying out finish rolling on the thick plate blank; tempering at low temperature to prepare a hot rolling steel plate; moulding and welding the steel plate; and expanding to manufacture the steel pipe with the yield strength of 485-630MPa, the tensile strength of 570-750MPa, uniform plastic deformation elongation of 8-15 percent, strain ageing sensitivity coefficient of not more than 0.40 and Charpy impact toughness of 220-350J at -20 DEG C.

Description

technical field [0001] The invention relates to a method for manufacturing pipeline steel and steel pipes whose strength level reaches X70 and X80 high steel grade and large strain (strain aging sensitivity coefficient is not more than 0.40). Background technique [0002] my country's oil and gas pipeline projects have developed rapidly, especially the construction of long-distance transmission pipelines has been greatly developed in recent years, and the pipelines must pass through various complex geological and geomorphic conditions. The stress-based design method is used for pipelines in most areas, but the strain-based pipeline design method must be used when the pipeline passes through seismic zones, active faults, subsidence zones, tundra zones, landslide zones, etc. High-grade pipeline steel with large uniform plastic deformation capacity and develop corresponding manufacturing technology. Generally speaking, the uniform plastic deformation capacity is larger when th...

Claims

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Application Information

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IPC IPC(8): C22C38/04C22C38/14C22C33/04C21D8/02F16L9/02
Inventor 冯耀荣吉玲康陈宏远陈宏达李鹤林杨龙
Owner BC P INC CHINA NAT PETROLEUM CORP
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