CN101805822A - Thermal treatment method of 15CrMoG steel annular welding line - Google Patents
Thermal treatment method of 15CrMoG steel annular welding line Download PDFInfo
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- CN101805822A CN101805822A CN 201010146663 CN201010146663A CN101805822A CN 101805822 A CN101805822 A CN 101805822A CN 201010146663 CN201010146663 CN 201010146663 CN 201010146663 A CN201010146663 A CN 201010146663A CN 101805822 A CN101805822 A CN 101805822A
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Abstract
The invention discloses a thermal treatment method of a 15CrMoG steel annular welding line, which has better effect of preventing delayed cracks and is more stable. The thermal treatment method comprises the following steps of: wrapping the welding line of the electric heater by applying a crawler belt type electric heater and an electric heater automatic temperature controller in signal connection with the electric heater; covering a heat insulating layer which has the thickness of 45-55mm and is made from aluminum silicate cottons outside the electric heater; carrying out thermal treatment on a part of the welding line with a temperature-raising speed of 150-220 DEG C/h; controlling the temperature-raising speed to be no less than 205*25/delta and no more than 330 DEG C/h when the temperature is raised to 400 DEG C, wherein the delta is the thickness of a wall of a base metal and the unit is mm; keeping the temperature for 45-70min when the temperature is raised to 650-750 DEG C, and then instantly lowering the temperature with the temperature-lowering speed of 100-260 DEG C/h; and naturally cooling the welding part after the temperature is reduced to 400-300 DEG C. The method greatly reduces crack occurrence rates after welding, improves the welding quality and the work efficiency with stable welding quality, is mainly applied to the thermal treatment of the 15CrMoG steel annular welding line, and can be used as a reference for preventing the crack of linear welding line of 15CrMoG steel and other heat-resistant alloy steel types.
Description
Technical field
The present invention relates to a kind of method that the back butt welded seam is heat-treated, especially a kind of 15CrMoG heat-resisting alloy steel circumferential weld heat treating method of welding.
Background technology
The 15CrMoG steel is a kind of heat-resisting alloy steel, be commonly used for pressure pipeline, its why can be under 350～550 ℃ high temperature work steady in a long-term, be because it has than better mechanical behavior under high temperature of general soft steel and high-temperature oxidation resistance, because general carbon steel is when high temperature, not only intensity is low, and oxidation can take place, and temperature is high more, oxidation is serious more, and ferric oxide is very careless, thereby causes oxidising process constantly to be carried out to steel inside, quickens the destruction of steel.If in steel, add chromium, then, during high temperature, at first form chromic oxide in the metallic surface because the avidity of chromium and oxygen is bigger than the avidity of iron and oxygen, fine and close oxidation is ironed at metallic surface formation layer protecting film, thereby can prevent that interior metal is subjected to oxidation.
According to " GB5310-2008 " the 6th page that implements in Standardization Administration of China's issue on October 24th, 2008, on October 1st, 2009, the chemical ingredients of 15CrMoG steel is: C:0.12-0.18%, Si:0.17-0.37%, Mn:0.40-0.7%, Cr:0.80-1.10%, Mo:0.40-0.55%, S≤0.025%, P≤0.015%.
Because contain Cr, Mo and other alloying element of high level in the 15CrMoG steel, the tendency of hardenability of steel is more obvious, weldability is poor.Formula by international welding association recommendation:
Ceq=C+Mn/6+ (Cr+Mo+V)/5+ (Ni+Cu)/15 calculates, and its carbon equivalent is generally more than 0.5%.Rule of thumb: when Ceq＞0.4%, the welding joint tendency of hardenability is big, just cold crack may appear, so the tendency of hardenability of 15CrMoG steel is big, weldability is poor, simultaneously, the crackle that the 15CrMoG heat-resisting alloy steel produces has retardance, just postwelding did not split at that time, treated that weldment crackle just occurs after cooling for some time, therefore exists big potential safety hazard.
The existing method that prevents to 15CrMoG steel loop shape weld seam (being generally pipe welding seam) crackle has two kinds, and a kind of is the requirement that improves preceding preheating of butt welding and welding operation, and postwelding carries out ray or ultrasonic inspection and visual inspection, just reprocesses if any crackle; The 2nd, postwelding is heat-treated, general heat treating method commonly used is: in the artificial flame heating of postwelding, usually be heated to and promptly 200～300 ℃ of the approaching temperature of weld preheating, be incubated slow cooling then to the welding envrionment temperature, postwelding crackle occurrence rate is lower than preceding a kind of method under this kind method, but the operative employee of different skill levels operation just has different occurrence rates, treatment effect to be difficult to hold.
Summary of the invention
In order to overcome the existing unsettled deficiency of 15CrMoG steel loop shape weld seam heat treating method effect, technical problem to be solved by this invention provides a kind of better and more stable 15CrMoG steel loop shape weld seam heat treating method of delayed cracking effect that prevents.
The technical solution adopted for the present invention to solve the technical problems is: 15CrMoG steel loop shape weld seam heat treating method, heat-treat at the butt welded seam position, heat-up rate is 150～220 ℃/h, to temperature rises to 400 ℃ time control heat-up rate≤205 * 25/ δ and≤330 ℃/h, wherein δ is the mother metal wall thickness, the mm of unit, after being raised to 650～750 ℃, temperature is incubated 45～75min, immediately the cooling, cooling rate is 100～260 ℃/h, drop to 400～300 ℃ after naturally cooling.
During mother metal wall thickness δ≤25mm, the control heat-up rate is 200～220 ℃/h, is incubated 65～75 minutes after temperature rises to 700～750 ℃, cooling immediately, cooling rate is 100～150 ℃/h, drop to 350～300 ℃ after naturally cooling.
The electric heater automatic temperature control instrument of using the track type electric heater and being connected with described electric heater signal carries out the thermal treatment at weld seam position, holds weld seam with described electric heater.
At described electric heater external parcel thermal insulation layer.
Described thermal insulation layer is made with aluminium silicate wool, and thickness is 45～55mm.
The invention has the beneficial effects as follows: heat-treat with method butt welded seam of the present invention, that is pipeline is carried out the partial heat treatment of postwelding, can reduce postwelding crackle occurrence rate greatly, improve welding quality and working efficiency, and welding quality is more stable, be mainly used in the thermal treatment of 15CrMoG steel loop shape weld seam, also can use for reference reference for 15CrMoG steel straight bead and other heat-resisting alloy steel kinds prevention postwelding crackle.
Embodiment
The present invention is further described below in conjunction with embodiment.
15CrMoG steel loop shape weld seam heat treating method of the present invention, the electric heater automatic temperature control instrument of using the track type electric heater and being connected with described electric heater signal, described electric heater is held weld seam, heat-treat at the butt welded seam position, heat-up rate is 150～220 ℃/h, to temperature rises to 400 ℃ time control heat-up rate≤205 * 25/ δ and≤330 ℃/h, wherein δ is the mother metal wall thickness, the mm of unit, after being raised to 650～750 ℃, temperature is incubated 45～70min, immediately the cooling, cooling rate is 100～260 ℃/h, drop to 400～300 ℃ after naturally cooling.
According to the welding of 15CrMoG steel conduit repeatedly postheat treatment record is summarized, the check of contrast postwelding crackle, find to adopt " heat-up rate is 150～220 ℃/h; when temperature rises to 400 ℃ control heat-up rate≤205 * 25/ δ and≤330 ℃/h; wherein δ is the mother metal wall thickness; the mm of unit; be incubated 45～70min after temperature is raised to 650～750 ℃; cooling immediately, cooling rate is 100～260 ℃/h, drops to naturally cooling after 400～300 ℃ " heat treatment process, its weldquality is reliable and stable; qualification rate is near 100%, and postwelding delayed cracking occurrence rate reduces greatly.
Rule of thumb, during mother metal wall thickness δ≤25mm, should get heat-up rate is 200～220 ℃/h, should get 700～750 ℃ for temperature-rise period end temp scope, and corresponding getting than long soaking time at 65～75 minutes, immediately the cooling, cooling rate should be got 100～150 ℃/h, drop to 350～300 ℃ after naturally cooling.
In addition, for 650～750 ℃ of temperature-rise period end temp scopes,, otherwise get high value as the higher desirable low value of envrionment temperature; For 400～300 ℃ of non-natural cooling process end temp scopes,, otherwise get low value as the higher desirable high value of envrionment temperature.
The electric heater automatic temperature control instrument that adopts the track type electric heater and be connected with described electric heater signal can be controlled heat treated heating-cooling process exactly, simultaneously, because of electric heater holds weld seam, with respect to existing flame heating mode, weld seam is heated more even, helps improving the stability of thermal effectiveness.
For the described heat treatment process of convenient realization, improve heat rate, should be wrapped with thermal insulation layer at described electric heater.
Described thermal insulation layer is made with aluminium silicate wool, and thickness is 45～55mm.
Embodiment:
The pipeline welding process of 15CrMoG steel: the welding preheating, adopt welding wire PP.TIG-R30, specification is the welding wire gas turbine arc welding bottoming of Φ 2.5; The employing trade mark is CHH307, and specification is the electrode arc welding capping of Φ 3.2 * 350, and postwelding is heat-treated.
Handle example 1
Pipeline specifications:
Weld seam quantity 20 roads, ambient temperature during operation: about 20～25 ℃ of normal temperature, the heat treatment process parameter of selection is: rate of heating is 150 ℃/h, when temperature rose to 400 ℃, rate of heating was 330 ℃/h.Insulation was 45 minutes after temperature was raised to 650 ℃, naturally cooling when dropping to 400 ℃ with 100 ℃/h of cooling rate.
Result: adopt ray and ultrasonic inspection to check have weld seam part, 2 road that crackle is arranged in the 20 road weld seams, qualification rate 90%, weld seam after Overheating Treatment is measured the hardness value of weld seam and heat affected zone with hardness tester, its hardness value meets the regulation of design document, be that the 15CrMoG pipe welding seam should not be greater than 125% of mother metal hardness 170, the hardness value of heat affected zone is not more than mother metal hardness.
Handle example 2
Pipeline specifications:
Weld seam quantity 20 roads, ambient temperature during operation: the about 20-25 of normal temperature ℃, the heat treatment process parameter of selection is: rate of heating is 200 ℃/h, when temperature rose to 400 ℃, rate of heating was 330 ℃/h.After temperature is raised to 700 ℃ the insulation 60 minutes, cooling rate is 180 ℃/h, drop to 350 ℃ after naturally cooling.
Result: adopt ray and ultrasonic inspection to check that 20 road weld seams are all qualified, qualification rate 100%, weld seam after Overheating Treatment is measured the hardness value of weld seam and heat affected zone with hardness tester, its hardness value meets the regulation of design document, be that the 15CrMoG pipe welding seam should not be greater than 125% of mother metal hardness 170, the hardness value of heat affected zone is not more than mother metal hardness.
Handle example 3
Pipeline specifications:
Weld seam quantity 20 roads, ambient temperature during operation: the about 20-25 of normal temperature ℃, the heat treatment process parameter of selection is: rate of heating is 220 ℃/h, when temperature rose to 400 ℃, rate of heating was 330 ℃/h.After temperature is raised to 750 ℃ the insulation 70 minutes, cooling rate is 260 ℃/h, drop to 300 ℃ after naturally cooling.
Result: adopt ray and ultrasonic inspection to check that 20 road weld seams are all qualified, qualification rate 100%, weld seam after Overheating Treatment is measured the hardness value of weld seam and heat affected zone with hardness tester, there is the hardness value of 5 road weld seams not meet the regulation of design document, be that the 15CrMoG pipe welding seam should not be greater than 125% of mother metal hardness 170, the hardness value of heat affected zone is not more than mother metal hardness.
The dimensional parameters unit that relates to specification among the above embodiment is mm.
Claims (5)
1.15CrMoG steel loop shape weld seam heat treating method, it is characterized in that: heat-treat at the butt welded seam position, heat-up rate is 150～220 ℃/h, to temperature rises to 400 ℃ time control heat-up rate≤205 * 25/ δ and≤330 ℃/h, wherein δ is the mother metal wall thickness, the mm of unit, after being raised to 650～750 ℃, temperature is incubated 45～75min, immediately the cooling, cooling rate is 100～260 ℃/h, drop to 400～300 ℃ after naturally cooling.
2. 15CrMoG steel loop shape weld seam heat treating method as claimed in claim 1, it is characterized in that: during mother metal wall thickness δ≤25mm, the control heat-up rate is 200～220 ℃/h, after rising to 700～750 ℃, temperature is incubated 65～75 minutes, cooling immediately, cooling rate is 100～150 ℃/h, drop to 350～300 ℃ after naturally cooling.
3. 15CrMoG steel loop shape weld seam heat treating method as claimed in claim 1 or 2, it is characterized in that: application track type electric heater and the electric heater automatic temperature control instrument that is connected with described electric heater signal carry out the thermal treatment at weld seam position, hold weld seam with described electric heater earlier.
4. 15CrMoG steel loop shape weld seam heat treating method as claimed in claim 3 is characterized in that: at described electric heater external parcel thermal insulation layer.
5. 15CrMoG steel loop shape weld seam heat treating method as claimed in claim 4, it is characterized in that: described thermal insulation layer is made with aluminium silicate wool, and thickness is 45～55mm.
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| CN 201010146663 CN101805822A (en) | 2010-04-14 | 2010-04-14 | Thermal treatment method of 15CrMoG steel annular welding line |
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| CN 201010146663 CN101805822A (en) | 2010-04-14 | 2010-04-14 | Thermal treatment method of 15CrMoG steel annular welding line |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104451076A (en) * | 2014-12-31 | 2015-03-25 | 无锡透平叶片有限公司 | Method for conducting partial heat treatment on martensitic precipitated hardening stainless steel after repair welding |
| CN104517002A (en) * | 2014-09-02 | 2015-04-15 | 中国石油天然气集团公司 | Test method for cooling crack sensitivity of pipeline girth weld |
| CN110541065A (en) * | 2019-08-19 | 2019-12-06 | 舞阳钢铁有限责任公司 | Postweld heat treatment process of chromium-molybdenum submerged arc welded pipe |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101622365A (en) * | 2007-01-17 | 2010-01-06 | Kva公司 | Use postweld heat treatment to improve the method for a seam welding performance |
| CN101624645A (en) * | 2009-08-04 | 2010-01-13 | 武汉科技大学 | Thermal treatment method for thinning weld metal structure |
-
2010
- 2010-04-14 CN CN 201010146663 patent/CN101805822A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101622365A (en) * | 2007-01-17 | 2010-01-06 | Kva公司 | Use postweld heat treatment to improve the method for a seam welding performance |
| CN101624645A (en) * | 2009-08-04 | 2010-01-13 | 武汉科技大学 | Thermal treatment method for thinning weld metal structure |
Non-Patent Citations (4)
| Title |
|---|
| 《中国电力》 20041130 冷祯皋 引进循环流化床锅炉15CrMo汽包管座与St45.8III降水管厚壁异口径高压管道的焊接 第60-63页 1-5 第37卷, 第11期 2 * |
| 《安装》 20060930 程早平等 15CrMo钢管焊接应注意的几个问题 第34-35页 1-5 , 第9期 2 * |
| 《焊接》 20011231 李熙莉 15CrMo钢管的焊后热处理工艺 第37-38页 1-5 , 第8期 2 * |
| 《焊管》 20080731 王敏 15CrMo钢管道的焊接 第72-73页 1-5 第31卷, 第4期 2 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104517002A (en) * | 2014-09-02 | 2015-04-15 | 中国石油天然气集团公司 | Test method for cooling crack sensitivity of pipeline girth weld |
| CN104451076A (en) * | 2014-12-31 | 2015-03-25 | 无锡透平叶片有限公司 | Method for conducting partial heat treatment on martensitic precipitated hardening stainless steel after repair welding |
| CN104451076B (en) * | 2014-12-31 | 2016-10-05 | 无锡透平叶片有限公司 | Case heat treating method after a kind of martensitic precipitation repair welding |
| CN110541065A (en) * | 2019-08-19 | 2019-12-06 | 舞阳钢铁有限责任公司 | Postweld heat treatment process of chromium-molybdenum submerged arc welded pipe |
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Open date: 20100818 |