CN103074544B - Cr-Mo-RE low-alloy seamless steel pipe for high-pressure boiler and manufacturing method of pipe - Google Patents
Cr-Mo-RE low-alloy seamless steel pipe for high-pressure boiler and manufacturing method of pipe Download PDFInfo
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- CN103074544B CN103074544B CN201310031375.XA CN201310031375A CN103074544B CN 103074544 B CN103074544 B CN 103074544B CN 201310031375 A CN201310031375 A CN 201310031375A CN 103074544 B CN103074544 B CN 103074544B
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Abstract
The invention discloses a Cr-Mo-RE (Rare Earth) low-alloy seamless steel pipe for a high-pressure boiler. The pipe comprises the following chemical components by mass percent: 0.05% -0.15% of C, 0.25% -0.50% of Si, 0.30% -0.60% of Mn, 1.2% -1.5% of Cr, 0.8% -1.0% of Mo, less than or equal to 0.025% of P, less than or equal to 0.025% of S, less than or equal to 0.04% of Al, 0.018% -0.022% of RE, and the balance of Fe and impurities, wherein the total mass percent is 100%. The invention further discloses a manufacturing method of the Cr-Mo-RE low-alloy seamless steel pipe for the high-pressure boiler. The pipe produced by the method has good high-temperature resistance and mechanical properties; the life cycle of the pipe is increased; and the safety of the pipe is improved.
Description
Technical field
The present invention relates to a kind of manufacturing technology of weldless steel tube, specifically, relate to a kind of Cr-Mo-RE low-alloy high-duty boiler weldless steel tube and manufacture method thereof.
Background technology
Along with the continuous increase of the pipe market share industrial shared by seamless tube, the seamless tube development be applied under varying environment also gos deep into year by year.The development of the effective high temperature steel of high-duty boiler originates in the '30s in last century.Start due to service temperature lower (≤450 DEG C), requirement of strength is not high, general some soft steel of employing (as 10#, 20# highquality carbon steel).Along with the development of power industry, in order to adapt to the needs that Boiler Steam parameter improves constantly, soft steel can not meet performance requriements, start to have occurred the low-alloy Refractory Steel containing Mo, its use temperature is in 450 DEG C to 520 DEG C temperature ranges, its creep rupture strength than 20# steel height 1.5-2.0 doubly, can say that the development of Mo steel is the source of low-alloy Refractory Steel development in modern age.After this Cr-Mo system, Cr-Mo-V series low-alloy high temperature steel and for high Cr (containing the Cr:9-12%) steel of ultra supercritical station boiler unit and superalloy has been developed again.
As everyone knows, rare earth adds in steel in right amount as alloying element, can cleaning molten steel, make harmful to be mingled with the effect such as sex change and deoxidation alloying, improve steel comprehensive mechanical property, corrosion resistance, antioxidant property and thermotolerance.So add trace rare-earth in Cr-Mo system steel alloy, replace a part of Cr to reduce alloy total amount and reach the object improving material at high temperature mechanical property.To reduce material cost, to improve its over-all properties as invention starting point be significantly.
Summary of the invention
Technical problem solved by the invention is to provide a kind of Cr-Mo-RE low-alloy high-duty boiler weldless steel tube, and tubing has good high temperature resistant mechanical property, improves life cycle and the safety performance of tubing.
Technical scheme is as follows:
A kind of Cr-Mo-RE low-alloy high-duty boiler weldless steel tube, tubing comprises according to the chemical composition of mass percent: C0.05 ~ 0.15, Si0.25 ~ 0.50, Mn0.30 ~ 0.60, Cr1.2 ~ 1.5, Mo0.8 ~ 1.0, P≤0.025, S≤0.025, Al≤0.04, rare earth RE0.018 ~ 0.022, all the other are for Fe and be mingled with, and massfraction amounts to 100%.
Further: tubing is according in the chemical composition of mass percent, and C is 0.13, Si be 0.31, Mn be 0.32, Cr be 1.2, Mo be 0.6, P be 0.016, S be 0.003, Al be 0.03, RE is 0.02.
Another technical problem solved by the invention is to provide a kind of manufacture method of Cr-Mo-RE low-alloy high-duty boiler weldless steel tube, and the tubing of production has good high temperature resistant mechanical property, improves life cycle and the safety performance of tubing.
Technical scheme is as follows:
A kind of manufacture method of Cr-Mo-RE low-alloy high-duty boiler weldless steel tube, smelt through material and form weldless steel tube after weldless steel tube hot continuous rolling two steps, the step that material is smelted comprises blast-melted smelting, converter smelting, liquid steel refining and continuous casting of molten steel and forms round steel billet; Wherein, in converter smelting, molten iron after pretreatment enters converter, and oxygen decarburization heats up, and the smelting later stage adds ferrosilicon, ferromanganese, ferrochrome and molybdenum-iron deoxidation alloying, and control P and S composition, prevent molten steel peroxidation, tapping temperature 1600 ~ 1630 DEG C; Liquid steel refining adopts the omnidistance gon technics of ladle refining furnace LF+ vacuum degassing furnace VD, evenly adds C powder and Si powder in batches, fully reduces, keep reducing atmosphere, adopt the deoxidation of Al silk in refining process, and later stage employing rare earth feeds silk technology to be made RE alloyed; Enter VD stokehold, temperature is 1610 ~ 1630 DEG C, w [S]≤0.007%; LF stove refining time controls at 45-60 minute, first carries out thermometric after entering VD stove seat bag, temperature is controlled at >=1620 DEG C, then to enter VD stove evacuation, vacuum tightness≤0.10KPa, dark vacuum time >=15min; Continuous casting of molten steel is formed in steel billet process, and molten steel enters tundish temperature and controls at 1550-1580 DEG C, superheating temperature Δ T≤30 DEG C, casting speed control at 0.65-0.75m/min, straightening temperature >=950 DEG C; In weldless steel tube Hot Strip Rolling, steel billet adopts ring furnace heating, after having heated, enters conic perforator perforation, and during its circle base perforation, temperature is 1200 ~ 1260 DEG C; Rear employing of having bored a hole is micro-draws steel rolling rolling, and during tube rolling, temperature is 1050 ~ 1150 DEG C; To enter after reheating furnace heating through stretch-reducing mill wroughtsteel pipe to final size, fixed temperature when subtracting is 820 ~ 900 DEG C, finally formation Cr-Mo-RE low-alloy high-duty boiler weldless steel tube; Weldless steel tube tubing is according to the chemical composition of mass percent, comprise: C0.05 ~ 0.15, Si0.25 ~ 0.50, Mn0.30 ~ 0.60, Cr1.2 ~ 1.5, Mo0.8 ~ 1.0, P≤0.025, S≤0.025, Al≤0.04, rare earth RE0.018 ~ 0.022, all the other are for Fe and be mingled with, and massfraction amounts to 100%.
Further: tubing is according in the chemical composition of mass percent, and C is 0.13, Si be 0.31, Mn be 0.32, Cr be 1.2, Mo be 0.6, P be 0.016, S be 0.003, Al be 0.03, RE is 0.02.
Technique effect comprises:
The present invention adds trace rare-earth in Cr-Mo system steel alloy, forms Cr-Mo-RE low-alloy high pressure boiler tube, meets the demand that Boiler Steam parameter improves constantly to greatest extent.Under severe service condition, tubing has good strength, toughness and mechanical property, and good high temperature resistant mechanical property, improves life cycle and the safety performance of tubing, meets the strict demand of GB to high-duty boiler seamless tube.
Improve the starting point of its over-all properties as invention to reduce material cost, obtain the success of large-scale commercial production, there is good promotional value.
Accompanying drawing explanation
Fig. 1 is the comparison diagram of each example yield strength in the present invention;
Fig. 2 is the comparison diagram of each example tensile strength in the present invention;
Fig. 3 is the comparison diagram of each example elongation in the present invention.
Embodiment
The present invention adds trace rare-earth in Cr-Mo system steel alloy, replaces a part of Cr to reduce alloy total amount and reaches the object improving material at high temperature mechanical property.Steel-smelting production process is: molten iron → converter steelmaking → LF refining → VD is degassed → and round billet continuous casting.Converter smelting adopts the pre-desulphurised hot metal of KR (hot metal in steelmaking pre-treatment), ferrosilicon, ferromanganese, ferrochrome and ferro-molybdenum deoxidation alloying, and rare earth feeds silk technology, and whole process is by the normal Argon of refining; Vacuum tightness≤0.10KPa, dark vacuum time >=13min, condensate depression Δ T≤30 DEG C.Rolling technology is: → warehouse-in is marked → weighed to circle base → sawing → ring furnace heating → perforation → PQF tandem rolling → stepped start-stop system reheating furnace → tension reducing → cold bed → scale → aligning → eddy current test → manual detection, spray.
LF stove (LADLEFURNACE) i.e. ladle refining furnace is external refining equipment main in Iron and Steel Production.VD type ladle refining furnace is alloying constituent fine setting under oxygen blast under vacuo, decarburization, vacuum stripping, vacuum, is mainly used in refining ultra low-carbon steel and electrical pure iron etc.; Under VD type ladle refining furnace can carry out general Fruit storage and vacuum to molten steel, alloying constituent is finely tuned.
Below the production process of tubing in the present invention is illustrated.
1. material is smelted
1.1 carry out molten iron smelting;
1.2 converter smelting;
Molten iron after pretreatment enters converter, oxygen decarburization heats up, and the smelting later stage adds ferrosilicon, ferromanganese, ferrochrome and molybdenum-iron (specific chemical composition is as shown in table 1 below) deoxidation alloying, control P, S composition, prevent molten steel peroxidation, tapping temperature 1600 ~ 1630 DEG C.
The various alloy material main chemical compositions of table 1 (mass percent, %)
| Title | C | Si | S | P | Mn | Cr | Mo | Fe |
| Ferromanganese | 7.5-8.5 | 1.5-2.5 | 0.02-0.05 | 0.2-0.33 | 75-82 | - | - | Residue |
| Ferrochrome | 5.5-6.5 | 3.0-4.0 | 0.04-0.06 | 0.02-0.04 | - | 62-72 | - | Residue |
| Molybdenum-iron | 0.08-0.12 | 1.4-1.6 | 0.08-0.12 | 0.04-0.07 | - | - | 65-75 | Residue |
| Ferrosilicon | 0.18-0.24 | 72-80 | 0.02-0.03 | 0.035-0.045 | 0.5-0.6 | 0.5-0.6 | - | - |
1.3 liquid steel refining;
Adopt ladle refining furnace (LF, LADLEFURNACE)+vacuum degassing furnace (VD) omnidistance gon technics, C, Si powder is evenly added in batches in refining process, abundant reduction, keep good reducing atmosphere, adopt the deoxidation of Al silk, the later stage adopts rare earth hello silk technology (rare earth alloy material is mishmetal, mainly based on cerium) to make RE alloyed.Enter VD stokehold, temperature is 1610 ~ 1630 DEG C; W [S]≤0.007%.LF stove refining time controls at 45-60 minute; First carry out thermometric after entering VD stove seat bag, temperature is controlled at >=1620 DEG C, then enter VD stove evacuation, vacuum tightness≤0.10KPa, dark vacuum time >=15min.
1.4 continuous casting of molten steel form steel billet;
Molten steel enters tundish temperature and controls at 1550-1580 DEG C, and superheating temperature Δ T≤30 DEG C, casting speed control is at 0.65-0.75m/min.Is furnished with electromagnetic agitating technology, dynamic soft reduction technology, straightening temperature >=950 DEG C.
2. weldless steel tube hot continuous rolling
Steel billet adopts ring furnace heating (each district temperature is as shown in table 2 below), after having heated, (gripping angle, guide plate distance, position, top and hot tool adjust according to different size seamless tube to enter conic perforator successively,) perforation, during its circle base perforation, temperature is 1200 ~ 1260 DEG C; PQF continuous mill (adopt micro-draw steel rolling) rolling, during tube rolling, temperature is 1050 ~ 1150 DEG C; Enter reheating furnace heating (or bypass), fixed according to practical situation, stretch-reducing mill wroughtsteel pipe is to final size, and determining to open temperature when subtracting is 820 ~ 900 DEG C, finally forms Cr-Mo-RE low-alloy high-duty boiler weldless steel tube.
The adjustable limiting mandrel tandem rolling pipe machine of three rods selects PQF continuous mill, and high-efficiency high-quality essence tube rolling mill (PQF, PremiumQualityFinishing) Italian INNSE company is that the inherent limitation overcoming two roller continuous mills develops.
Table 2 ring furnace each district Heating temperature
| Heated zones | Preheating zone | Heat 1st district | Heat 2nd district | Heat 3rd district | Heat 4th district | Heat 5th district | Soaking zone | To come out of the stove district |
| Temperature (DEG C) | With furnace temperature | 750±5 | 950±5 | 1100±5 | 1220±5 | 1290±5 | 1280±10 | 1240±5 |
Cr-Mo-RE low-alloy high-duty boiler weldless steel tube is according to the chemical composition of mass percent, comprise: C0.05 ~ 0.15, Si0.25 ~ 0.50, Mn0.30 ~ 0.60, Cr0.8 ~ 1.5, Mo0.8 ~ 1.0, P≤0.025, S≤0.025, Al≤0.04, rare earth RE0.018 ~ 0.022, all the other are for Fe and be unavoidably mingled with, and massfraction amounts to 100%.In the material composition of Cr-Mo-RE low-alloy high-duty boiler weldless steel tube, main alloy element Cr makes steel have good resistance to corrosion, and Mo improves the hot strength of steel, and RE makes steel have good toughness and solidity to corrosion.
3. material example is analyzed
3.1 material composition analyses
According to above smelting technology requirement, smelt the low-alloy high pressure boiler tube strand of following ingredients, concrete composition (mass percent) is as shown in table 3 below.
The each example chemical composition of table 3
3.2 Mechanics Performance Testing
Room-temperature mechanical property sample adopts bar-shaped sample, and 50mm calibrates distance, and specimen width is 12.7mm, and thickness is about 5.2mm.And about sample wall thickness, relevant correction is carried out on the correction regulation that unit elongation affects by ASMESA213/SA213M-01.Obtained experimental result is in table 4.
Table 4 material room temperature mechanical performance compare
3.3 high temperature, short time mechanical performance compares
As shown in Figure 1, the comparison diagram of each example yield strength in the present invention; Fig. 2 is the comparison diagram of each example tensile strength in the present invention; Fig. 3 is the comparison diagram of each example elongation in the present invention.
Contrast three examples can find out, the tubing that the technology of the present invention is produced has good strength, toughness and mechanical property, the weldless steel tube prepared with it, and properties all can meet the requirement of GB to seamless steel tubes and pipes for high pressure boiler.To sum up Performance comparision, the selection of rare earth low-alloy high-duty boiler seamless tube is comparatively suitable.
Claims (4)
1. a Cr-Mo-RE low-alloy high-duty boiler weldless steel tube, it is characterized in that: tubing comprises according to the chemical composition of mass percent: C0.05 ~ 0.15, Si0.25 ~ 0.50, Mn0.30 ~ 0.60, Cr1.2 ~ 1.5, Mo0.8 ~ 1.0, P≤0.025, S≤0.025, Al≤0.04, rare earth RE0.018 ~ 0.022, all the other are for Fe and be mingled with, and massfraction amounts to 100%.
2. Cr-Mo-RE low-alloy high-duty boiler weldless steel tube as claimed in claim 1, is characterized in that: tubing is according in the chemical composition of mass percent, and C is 0.13, Si is 0.31, Mn is 0.32, Cr be 1.2, Mo be 0.6, P is 0.016, S is 0.003, Al be 0.03, RE is 0.02.
3. the manufacture method of a Cr-Mo-RE low-alloy high-duty boiler weldless steel tube, smelt through material and form weldless steel tube after weldless steel tube hot continuous rolling two steps, it is characterized in that: the step that material is smelted comprises blast-melted smelting, converter smelting, liquid steel refining and continuous casting of molten steel and forms round steel billet; Wherein, in converter smelting, molten iron after pretreatment enters converter, and oxygen decarburization heats up, and the smelting later stage adds ferrosilicon, ferromanganese, ferrochrome and molybdenum-iron deoxidation alloying, and control P and S composition, prevent molten steel peroxidation, tapping temperature 1600 ~ 1630 DEG C; Liquid steel refining adopts the omnidistance gon technics of ladle refining furnace LF+ vacuum degassing furnace VD, evenly adds C powder and Si powder in batches, fully reduces, keep reducing atmosphere, adopt the deoxidation of Al silk in refining process, and later stage employing rare earth feeds silk technology to be made RE alloyed; Enter VD stokehold, temperature is 1610 ~ 1630 DEG C, w [S]≤0.007%; LF stove refining time controls at 45-60 minute, first carries out thermometric after entering VD stove seat bag, temperature is controlled at >=1620 DEG C, then to enter VD stove evacuation, vacuum tightness≤0.10KPa, dark vacuum time >=15min; Continuous casting of molten steel is formed in steel billet process, and molten steel enters tundish temperature and controls at 1550-1580 DEG C, superheating temperature Δ T≤30 DEG C, casting speed control at 0.65-0.75m/min, straightening temperature >=950 DEG C; In weldless steel tube Hot Strip Rolling, steel billet adopts ring furnace heating, after having heated, enters conic perforator perforation, and during its circle base perforation, temperature is 1200 ~ 1260 DEG C; Rear employing of having bored a hole is micro-draws steel rolling rolling, and during tube rolling, temperature is 1050 ~ 1150 DEG C; To enter after reheating furnace heating through stretch-reducing mill wroughtsteel pipe to final size, fixed temperature when subtracting is 820 ~ 900 DEG C, finally formation Cr-Mo-RE low-alloy high-duty boiler weldless steel tube; Weldless steel tube tubing is according to the chemical composition of mass percent, comprise: C0.05 ~ 0.15, Si0.25 ~ 0.50, Mn0.30 ~ 0.60, Cr1.2 ~ 1.5, Mo0.8 ~ 1.0, P≤0.025, S≤0.025, Al≤0.04, rare earth RE0.018 ~ 0.022, all the other are for Fe and be mingled with, and massfraction amounts to 100%.
4. the manufacture method of Cr-Mo-RE low-alloy high-duty boiler weldless steel tube as claimed in claim 3, it is characterized in that: tubing is according in the chemical composition of mass percent, C is 0.13, Si be 0.31, Mn is 0.32, Cr is 1.2, Mo is 0.6, P be 0.016, S is 0.003, Al is 0.03, RE is 0.02.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310031375.XA CN103074544B (en) | 2013-01-28 | 2013-01-28 | Cr-Mo-RE low-alloy seamless steel pipe for high-pressure boiler and manufacturing method of pipe |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310031375.XA CN103074544B (en) | 2013-01-28 | 2013-01-28 | Cr-Mo-RE low-alloy seamless steel pipe for high-pressure boiler and manufacturing method of pipe |
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| CN103074544A CN103074544A (en) | 2013-05-01 |
| CN103074544B true CN103074544B (en) | 2015-03-04 |
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| CN103215518B (en) * | 2013-05-14 | 2016-04-20 | 内蒙古包钢钢联股份有限公司 | Containing the resistance to H of rare earth 2the preparation method of S corroded pipeline weldless steel tube |
| CN104911490A (en) * | 2015-04-27 | 2015-09-16 | 内蒙古包钢钢联股份有限公司 | 13Cr1Mo1V heat resistant seamless steel pipe and seamless preparation method |
| CN113025902B (en) * | 2021-03-04 | 2022-02-01 | 东北大学 | Hot-rolled seamless steel tube with excellent toughness and manufacturing method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1360081A (en) * | 2001-07-17 | 2002-07-24 | 束润涛 | Low-alloy rare-earth steel resisting corrosion of hydrogen sulfide |
| CN102534388A (en) * | 2011-12-07 | 2012-07-04 | 内蒙古包钢钢联股份有限公司 | Rare earth containing H2S-corrosion resistance petroleum casing pipe and production method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0250912A (en) * | 1988-08-11 | 1990-02-20 | Nippon Steel Corp | Production of low alloy high tension seamless steel pipe having fine grained structure |
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- 2013-01-28 CN CN201310031375.XA patent/CN103074544B/en not_active Withdrawn - After Issue
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1360081A (en) * | 2001-07-17 | 2002-07-24 | 束润涛 | Low-alloy rare-earth steel resisting corrosion of hydrogen sulfide |
| CN102534388A (en) * | 2011-12-07 | 2012-07-04 | 内蒙古包钢钢联股份有限公司 | Rare earth containing H2S-corrosion resistance petroleum casing pipe and production method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 李奇 等.高压锅炉用无缝钢管.《中华人民共和国国家标准GB5310-2008》.2008,第6页表3钢序号8. * |
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