CN102492821A - Heat treatment process for fine grain austenitic steel pipe bend - Google Patents
Heat treatment process for fine grain austenitic steel pipe bend Download PDFInfo
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- CN102492821A CN102492821A CN2011104544260A CN201110454426A CN102492821A CN 102492821 A CN102492821 A CN 102492821A CN 2011104544260 A CN2011104544260 A CN 2011104544260A CN 201110454426 A CN201110454426 A CN 201110454426A CN 102492821 A CN102492821 A CN 102492821A
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Abstract
The invention discloses a heat treatment process for a fine grain austenitic steel pipe bend. The process comprises the following steps: carrying out heat treatment on the fine grain austenitic steel pipe bend in a heat treatment furnace at a temperature of 900 to 1050 DEG C for 2 to 120 min, discharging the bend out and cooling the bend by using air or water; detecting the hardness and the grain size of the bend after heat treatment is finished. The heat treatment process provided in the invention enables residual stress after pipe bending to be effectively eliminated, the grain size to be effectively controlled, excellent performance of fine grain austenitic stainless steel in a manufacture process to be retained and production cost to be saved.
Description
Technical field
The present invention relates to a kind of thermal treatment process of steel elbow, particularly, relate to a kind of thermal treatment process of fine grained austenite steel elbow.
Background technology
Along with developing rapidly of domestic station boiler industry, the vapor temperature and the pressure of boiler are increasingly high, and the performance of high-temperature heat-resistance material has also been had higher requirement, make the fine grained austenite stainless steel obtain number of applications.Compare with common austenitic stainless steel, the fine grained austenite stainless steel has better creep rupture strength and high temperature steam oxidation susceptibility.
Close grain is the guarantee that improves austenitic stainless steel high temperature resistance steam oxidation performance; Handle through grain refining; Can improve in the steam oxidation process Cr element to the passage of surface diffusion; Make steel tube surface form the fine and close sull of one deck more easily, thereby hinder the further oxidation of steel pipe, therefore in the manufacturing processed of boiler component, must control the stainless grain fineness number of fine grained austenite well.
In the manufacturing processed of reality, need carry out bend pipe processing to the fine grained austenite stainless-steel pipe, and, need carry out solution treatment after bending in order to eliminate the unrelieved stress of bend pipe.But recrystallize can take place in the elbow of fine grained austenite stainless-steel pipe inevitably in the solution treatment process.Recrystallize can be eliminated the internal stress of elbow effectively, eliminates the various performance change that viscous deformation caused.Grain fineness number behind the recrystallize and thermal treatment temp, time and bent pipe deformation have confidential relation, and thermal treatment temp is high more, and the time is long more, and bent pipe deformation is more near the critical strain amount, and the crystal grain behind the recrystallize is thick more.
As far as bend pipe, the outside of elbow has the maximum tension distortion, and the inboard has the maximum compression distortion, and is reduced to zero gradually along the circumferential two flank deflections of pipe.Elbow is in heat treatment process, and two flank deflections can sharply be grown up near the position crystal grain of critical strain amount, and thick crystal grain not only influences the mechanical property of steel pipe, also reduces the high temperature oxidation resistance at this place simultaneously.Solution to this problem mainly is through heat treatment process test, selects proper heat treatment technology, prevents grain growth in the heat treatment process, eliminates the unrelieved stress that flexural deformation produces.
At present domestic also do not have the good thermal treatment process that can address this problem, so press for a kind of new thermal treatment process of invention.
Summary of the invention
The purpose of this invention is to provide a kind of thermal treatment process that is used for the fine grained austenite steel elbow, can eliminate the internal stress behind the bend pipe effectively, can control grain fineness number effectively again, in manufacturing processed, keep the stainless premium properties of fine grained austenite.
In order to achieve the above object; The invention provides a kind of thermal treatment process of fine grained austenite steel elbow, this thermal treatment process comprises: in heat treatment furnace with the fine grained austenite steel elbow 900～1050 ℃ of coolings of coming out of the stove after carrying out the thermal treatment of 2～120min.
The thermal treatment process of above-mentioned fine grained austenite steel elbow, wherein, the described type of cooling adopts air cooling or water cooling.
Heat treatment process specifically is meant, heat treatment furnace is warmed up to the actual heat treatment temperature, then elbow is put into heat treatment furnace; Treat that furnace temperature is raised to the actual heat treatment temperature once more and picks up counting; Be incubated the specified time, elbow is taken out, carry out air cooling or water cooling.
, heat treatment process also should carry out the detection of elbow hardness and grain fineness number after finishing; Confirm whether the gained elbow satisfies grain fineness number and be narrower than 7 grades, the requirement of hardness≤200HV10, wherein HV representes that the test conditions that Vickers' hardness, HV10 are hardness test is the Vickers' hardness of load 10kg.
The thermal treatment process of fine grained austenite steel elbow provided by the invention; Be that orthogonal test through a series of thermal treatment temps and heat treatment time obtains; In 900 to 1150 ℃ of scopes, whenever get a temperature at a distance from 50 ℃; In 2-120min, choosing the heat treatment time of 2min, 30min, 60min, 120min heat-treats elbow; To the analysis that makes an experiment of hardness and the grain fineness number everywhere of elbow after the thermal treatment, obtain 900～1050 ℃ of TRs then, cooperate the soaking time of 2～120min comparatively favourable with the performance assurance the elbow stress relieving.
The thermal treatment process of fine grained austenite steel elbow provided by the invention has the following advantages:
This thermal treatment process prevents grain growth in the heat treatment process to fine grained austenite steel elbow, eliminates the unrelieved stress that flexural deformation produces, and after the thermal treatment, the elbow grain fineness number is narrower than 7 grades, and hardness≤200HV10 all can satisfy standard to raw-material requirement.Compare with the solution heat treatment of existing thermal treatment standard code, this thermal treatment process TR is relatively low, helps suppressing the elbow grain growth, improves the elbow performance, saves production cost simultaneously.
Description of drawings
Fig. 1 is the metallographic structure figure that the thermal treatment process of fine grained austenite steel elbow of the present invention is handled the back elbow.
Fig. 2 is the hardness test position view that the thermal treatment process of fine grained austenite steel elbow of the present invention is handled the back elbow.
Embodiment
Do explanation further below in conjunction with the accompanying drawing specific embodiments of the invention.
The thermal treatment process of fine grained austenite steel elbow provided by the invention; This thermal treatment process comprises: in heat treatment furnace with the fine grained austenite steel elbow 900～1050 ℃ of coolings of coming out of the stove after carrying out the thermal treatment of 2～120min, the type of cooling adopts air cooling or water cooling.
The thermal treatment temp that adopts in the present embodiment is 950 ℃, insulation 30min, air cooling.
Fine grained austenite stainless steel bend used in the present embodiment adopts the Super304H austenitic stainless steel, and its chemical ingredients is seen table 1.
Table 1: the chemical ingredients of fine grained austenite stainless steel bend (Wt%).
| Chemical element | C | Mn | Si | S | P | Cr |
| Measured value | 0.07 | 0.64 | 0.28 | 0.002 | 0.009 | 18.22 |
| Chemical element | Ni | Cu | Nb | N | Al | B |
| Measured value | 8.80 | 2.76 | 0.59 | 0.10 | 0.017 | 0.003 |
Thermal treatment detailed process in heat treatment furnace is: heat treatment furnace is warmed up to 950 ℃, then elbow is put into heat treatment furnace, treat that furnace temperature is raised to 950 ℃ once more and picks up counting, insulation 30min takes out elbow again, in air, cools off.
, this heat treatment process carries out the detection of elbow hardness and grain fineness number after finishing.
The detection of grain fineness number is through the metallography microscope sem observation and measure grain size, and the elbow grain fineness number should be narrower than 7 grades.As shown in Figure 1 in the present embodiment through the metallographic structure of elbow after the thermal treatment of metaloscope gained, can know after the measurement that the elbow grain fineness number is narrower than 7 grades.The instrument model is research inversion type opticmicroscope (Axio Observer.D1m).
Elbow hardness testing process is: heat-obtaining is handled the back elbow; Carry out cutting sampling in 0 ° at elbow, 45 °, 90 °, 135 ° positions; Referring to shown in Figure 2, obtain the hardness sample ring, on these hardness rings, pass through the hardness that Vickers hardness tester (VH-5DC) is measured different positions again; Measurement load is 10kg, and the measuring result of gained is seen table 2.
Table 2: elbow hardness test result after the thermal treatment.
Gained each item result all satisfies hardness≤200 HV10.HV representes Vickers' hardness, and the test conditions that HV10 is hardness test is the Vickers' hardness of load 10kg.
Thermal treatment process provided by the invention is applicable to one type of steel, comprises Super304H, and TP347HFG etc. are not only limited to preferred Super304H stainless steel in the present embodiment.
Although content of the present invention has been done detailed introduction through above-mentioned preferred embodiment, will be appreciated that above-mentioned description should not be considered to limitation of the present invention.After those skilled in the art have read foregoing, for multiple modification of the present invention with to substitute all will be conspicuous.Therefore, protection scope of the present invention should be limited appended claim.
Claims (2)
1. the thermal treatment process of a fine grained austenite steel elbow is characterized in that, this thermal treatment process comprises: in heat treatment furnace with the fine grained austenite steel elbow 900～1050 ℃ of coolings of coming out of the stove after carrying out the thermal treatment of 2～120min.
2. the thermal treatment process of fine grained austenite steel elbow as claimed in claim 1 is characterized in that, the described type of cooling adopts air cooling or water cooling.
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| CN2011104544260A CN102492821A (en) | 2011-12-30 | 2011-12-30 | Heat treatment process for fine grain austenitic steel pipe bend |
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| CN2011104544260A CN102492821A (en) | 2011-12-30 | 2011-12-30 | Heat treatment process for fine grain austenitic steel pipe bend |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106053322A (en) * | 2016-05-17 | 2016-10-26 | 上海锅炉厂有限公司 | Method for evaluating intergranular corrosion sensitivity of elbows made of austenite steel |
| CN111413185A (en) * | 2020-04-15 | 2020-07-14 | 重庆赛宝工业技术研究院 | Heat treatment method for detecting TP347HFG |
| CN112795759A (en) * | 2020-12-23 | 2021-05-14 | 二重（德阳）重型装备有限公司 | Method for accurately controlling size of large door-shaped three-dimensional stainless steel bent pipe |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1049379A (en) * | 1990-09-19 | 1991-02-20 | 能源部西安热工研究所 | Life-prolongging measure at labour Germany EBV st 45.8/III seamless steel tube for boiler |
| CN101358278A (en) * | 2008-07-21 | 2009-02-04 | 华电管道工程技术有限公司 | Intermediate frequency bent tube technique of heat-engine plant A335P92 steel |
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2011
- 2011-12-30 CN CN2011104544260A patent/CN102492821A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1049379A (en) * | 1990-09-19 | 1991-02-20 | 能源部西安热工研究所 | Life-prolongging measure at labour Germany EBV st 45.8/III seamless steel tube for boiler |
| CN101358278A (en) * | 2008-07-21 | 2009-02-04 | 华电管道工程技术有限公司 | Intermediate frequency bent tube technique of heat-engine plant A335P92 steel |
Non-Patent Citations (3)
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| 中华人民共和国国家质量监督检验检疫总局等: "锅炉和热交换器用奥氏体不锈钢焊接钢管", 《中华人民共和国国家标准GB/T24593-2009》, 30 October 2009 (2009-10-30), pages 1 - 9 * |
| 劳动部锅炉压力容器检测研究中心等合编: "《锅炉压力容器材料手册》", 29 February 1992, article "锅炉压力容器材料手册", pages: 254-258 * |
| 蒋荣明: "超高压再热机组锅炉制造探讨", 《江苏锅炉》, no. 4, 31 December 2004 (2004-12-31), pages 25 - 28 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106053322A (en) * | 2016-05-17 | 2016-10-26 | 上海锅炉厂有限公司 | Method for evaluating intergranular corrosion sensitivity of elbows made of austenite steel |
| CN111413185A (en) * | 2020-04-15 | 2020-07-14 | 重庆赛宝工业技术研究院 | Heat treatment method for detecting TP347HFG |
| CN112795759A (en) * | 2020-12-23 | 2021-05-14 | 二重（德阳）重型装备有限公司 | Method for accurately controlling size of large door-shaped three-dimensional stainless steel bent pipe |
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Application publication date: 20120613 |