US20160024626A1 - Stainless steel for hot forging and hot forging method using said steel - Google Patents

Stainless steel for hot forging and hot forging method using said steel Download PDF

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Publication number
US20160024626A1
US20160024626A1 US14/775,704 US201414775704A US2016024626A1 US 20160024626 A1 US20160024626 A1 US 20160024626A1 US 201414775704 A US201414775704 A US 201414775704A US 2016024626 A1 US2016024626 A1 US 2016024626A1
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traces
weight
stainless steel
recited
hot forging
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US14/775,704
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Francois Louis Marie ROCH
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Areva NP SAS
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Areva NP SAS
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum

Definitions

  • the present invention relates to stainless steel for the hot forging of large-size parts.
  • Ultrasound permeability is much dependent on grain size. If this microstructural characteristic becomes too large, permeability vanishes and some defects which may be contained in the part are no longer detectable. In addition the tensile mechanical properties are degraded if grain size becomes too large.
  • nuclear reactor boilers contain parts of large dimensions and complex geometry. These parts may be tubular branches for example of the primary cooling circuit having a very wide diameter and provided with branch points.
  • the hot forging of such parts requires the ingot to be held at a high temperature over a long period which may last several days. This may affect the microstructure of the steel via excessive enlarging of the grains. The mechanical properties of the part and its suitability for ultrasound inspection are thereby penalised.
  • micro-alloyed austenitic stainless steel for hot forging having the following composition in weight %:
  • the steel comprises one or more of the following characteristics taken alone or in any technically possible combination:
  • the niobium content (Nb) is 0.030 weight % or higher, in particular 0.035 weight % or higher;
  • the niobium content (Nb) is lower than 0.050 weight %, in particular 0.045 weight % or lower;
  • the carbon content (C) is lower than 0.05 weight %, preferably it is 0.02 weight % or lower;
  • the chromium content (Cr) is lower than 23 weight %;
  • the phosphorus content (P) is 0.04 weight % or lower and/or the sulfur content (S) is 0.03 weight % or lower;
  • the nitrogen content (N) is 0.1 weight % or lower
  • the steel has the following composition in weight %:
  • the steel has the following composition in weight %:
  • the steel has the following composition in weight %:
  • the steel has the following composition in weight %:
  • the steel has the following composition in weight %:
  • the steel has the following composition in weight %:
  • the invention also concerns a method for the hot forging of a part from an ingot of stainless steel such as defined above.
  • the method comprises one or more of the following characteristics taken alone or in any technically possible combination:
  • the ingot has an initial weight of 50 tonnes or higher, in particular 100 tonnes or higher;
  • the ingot is hot forged at a temperature of between 1300° C. and 1050° C., in particular at a temperature of between 1250° C. and 1150° C.;
  • hot forging is carried out for a period of time longer than 24 hours, in particular a period of time longer than 36 hours.
  • FIG. 1 is a schematic view illustrating steps of a method for manufacturing a part of large size by hot forging an ingot of stainless steel, more particularly a tubular element of the primary piping of a nuclear plant;
  • FIG. 2 is a functional graph illustrating the temperature of the stainless steel during the manufacture of the part.
  • the manufacturing method comprises a preliminary step to prepare the stainless steel which applies conventional processes and equipment used in an electric steel plant (electric furnace, refining devices, optionally re-melt devices) and the casting of the liquid metal into an ingot mould to solidify an ingot 2 that is to be forged.
  • an electric steel plant electric furnace, refining devices, optionally re-melt devices
  • the manufacturing method comprises a hot working step whereby the ingot 2 obtained is hot forged.
  • the ingot 2 gas a weight of several tens of tonnes, in particular more than 50 tonnes and more particularly more than 100 tonnes.
  • an ingot of over 150 tonnes is routinely used, in particular an ingot of about 170 tonnes.
  • the ingot 2 is of truncated cone shape with a diameter D in the order of 2566 mm and height in the order of 3735 mm.
  • the hot working process comprises heating of the ingot 2 to an initial temperature of between 1300 ° C. and 1050° C. and the hot forging of the ingot in successive steps to obtain a forging which forms the blank 4 of the part to be obtained.
  • FIG. 1 illustrates different steps of hot forging.
  • the blank 4 finally obtained is in the shape of an elongate element of variable diameter.
  • the diameter varies between 1050 mm and 2000 mm.
  • the manufacturing process finally comprises a machining step whereby the blank 4 is machined, for example to form ducts in the blank 4 , in particular a main duct and branch ducts leading into the main duct. Having regard to the dimensions of the part, machining typically takes several days.
  • FIG. 2 illustrates the temperature of the blank during hot forging as a function of time.
  • a first curve C 1 illustrates the trend in temperature at the core of the blank
  • curve C 2 illustrates the trend in temperature at one quarter depth of the blank
  • curve C 3 illustrates the temperature at half the depth of the blank
  • curve C 4 illustrates the temperature on the surface.
  • the hot forging operations on an ingot of heavy weight in the order of several tens of tonnes, last a long period of time. Typically these operations last more than 24 hours, in particular more than 48 hours and in some cases about ten days.
  • This hot forging can therefore be carried out in numerous steps alternately comprising hot working steps E 1 during which the blank 4 cools and re-heating steps E 2 during which the blank is heated.
  • FIG. 2 illustrates two forging steps each followed by a re-heating step.
  • the temperature is between a reheating temperature in the order of 1050° C. to 1300° C. and an end-of-forging temperature which varies in the thickness of the part and which may be in the order of 700° C. on the surface (curve C 4 ).
  • the stainless steel in held at a high temperature and over a long period of time, which may lead to irreversible changes in the microstructure of the stainless steel that are difficult to control, with resulting uncertainty that the part obtained will conform to specifications and is able to undergo ultrasonic testing.
  • the maintaining at high temperature for a long period promotes grain growth.
  • Grains that are too large in size have an influence on the mechanical properties of the steel at the end of manufacture and on the mechanical properties of the part.
  • grains that are too large are incompatible with ultrasonic testing as required in particular for the parts of nuclear reactor boilers.
  • the stainless steel used in the method of one embodiment of the invention is hot forged, micro-alloyed, austenitic stainless steel having the following composition in weight %:
  • This austenitic stainless steel has good mechanical properties, in particular satisfactory yield strength whilst avoiding grain growth even if held at a high temperature over a long period for hot forging.
  • Chromium (Cr) in a content of 16 weight % or higher imparts the stainless nature to the steel. It generates a protective passivation film.
  • a chromium content of 25 weight % or lower allows limiting of the onset of intermetallic phases which would weaken the stainless steel.
  • Molybdenum (Mo) also imparts the stainless characteristic to steel. Molybdenum contributes towards the formation of a passivation film and strengthens this film. In particular it increases resistance to pitting corrosion. The content of 6 weight % of lower prevents the onset of intermetallic phases which could weaken the stainless steel.
  • Copper (Cu) strengthens corrosion resistance. It has a stabilising effect on the passivation film.
  • Nickel (Ni) promotes the onset of austenitic structures.
  • a content of 8 weight % or higher allows austenitic steel to be obtained having good mechanical properties, in particular a very good compromise between yield strength and elongation.
  • a content of 25 weight % or lower allows a balance to be obtained between the chromium and nickel whilst limiting the amount of nickel which is a costly element.
  • Manganese (Mn) allows trapping of sulfur in the form of sulfur precipitates. It also promotes the onset of austenitic structures and allows limiting of the nickel content.
  • Tungsten has the same function as molybdenum. Tungsten is optional. The use of tungsten in addition to molybdenum allows limiting of the amount of molybdenum. Tungsten has a significant effect on corrosion resistance on and after a content of 0.5 weight %.
  • C carbon
  • a content of 0.08 weight % or less preferably 0.05% or less allows limiting of the formation of the chromium carbides which deplete the metal matrix of chromium and reduce corrosion resistance. It also limits the formation of niobium carbonitrides (Nb), in particular at the end of solidification (primary carbonitrides) which risk degrading some mechanical properties.
  • nitrogen is inevitable.
  • the limiting of nitrogen to a content of 0.1 weight % of less allows limiting of the excessive formation of carbonitrides, in particular the excessive formation of niobium carbonitride.
  • Silicon (Si), phosphorus (P) and sulfur (S) are inevitable and result from the process of steel making
  • Niobium allows limitation of grain growth. It has been observed that niobium reduces the hot recrystallization rate of steel both during forging (dynamic recrystallization) and during the reheating phases (static recrystallization). In addition niobium reduces grain growth rate during the long period of maintained high temperature when forging the steel. Having regard to the manufacturing time of a large-size forged part (typically several days) this moderating effect on grain size is most beneficial.
  • the niobium content of 0.015 weight % or higher allows satisfactory limitation of grain growth during hot forging, in particular when hot forging of a part from a steel ingot weighing several tens of tonnes.
  • the niobium content is 0.030 weight % or higher.
  • niobium content is too high there is a risk of the formation of large-size precipitates of niobium carbonitride, in particular towards the end of ingot solidification. Such precipitates risk degrading the mechanical properties of the steel.
  • a niobium content limited to 0.100 weight % allows satisfactory grain refining to be obtained by limiting the formation of niobium carbonitride precipitates.
  • the niobium content is 0.050% or lower.
  • the niobium content is between 0.030% and 0.050% which allows satisfactory grain refining whilst preserving the mechanical properties of the steel in particular its yield strength. In one preferred embodiment it is between 0.035% and 0.045%. In one particular embodiment it is about 0.040%.
  • Vanadium (V) and titanium (Ti) are carbide-forming elements which may cause the precipitation of vanadium carbides or titanium carbides which trap the carbon and limit the formation of chromium carbide. The formation of such precipitates increases the mechanical properties of the stainless steel, in particular yield strength (Rm). Vanadium has a significant effect on and after a content of 0.05 weight %. Titanium has a significant effect on and after a content of 0.02 weight %.
  • Boron (B) allows an improvement in the mechanical properties of the steel, in particular its yield strength. Boron has a significant effect on and after a content of 0.0015 weight %.
  • the stainless steel has the following composition in weight %:
  • This stainless steel corresponds to type 304 steel as per the AISI standard (American Iron and Steel Institute).
  • the stainless steel has the following composition in weight %:
  • This stainless steel corresponds to type 304L steel as per the AISI standard (American Iron and Steel Institute). Its composition differs from the composition of grade 304 steel in particular through its lower carbon content. Grade 304L steel has higher corrosion resistance than 304 steel.
  • the stainless steel has the following composition in weight %:
  • This stainless steel corresponds to steel of 316 type in accordance with the AISI standard.
  • the stainless steel has the following composition in weight %:
  • This stainless steel corresponds to type 316L steel according to the AISI standard.
  • the stainless steel has the following composition in weight %:
  • This stainless steel corresponds to A904L as per the AISI standard.
  • This steel has particularly high corrosion resistance, in particular higher than that of 304, 304L, 316, 316L steel grades.
  • the niobium content is preferably 0.030% or higher, preferably it is 0.0035% and/or 0.050% or lower, preferably 0.045%. In one particular embodiment it is about 0.040%.
  • the table below gives the analyses of niobium-containing micro-alloyed stainless steels which allowed evidencing of the beneficial effect of this element on grain size.
  • the table indicates the weight % composition of each species, the remainder being iron and inevitable manufacturing impurities.
  • the species which are not mentioned in the table (B, W, P . . . ) are only contained in trace form.
  • Example 1 19.3 9.6 0.35 1.67 0.0671 0.026 0.053 — — — Example 2 19.2 9.6 0.34 1.65 0.0681 0.026 0.016 — — Example 3 17.5 12.2 2.21 1.52 0.0603 0.021 0.043 — — — Example 4 21.8 24.9 4.74 1.81 0.0615 0.027 0.039 — — 1.61
  • Examples 1 and 2 correspond to niobium-containing micro-alloyed steels of grade 304L according to embodiments of the invention
  • Example 3 corresponds to niobium-containing micro-alloyed steel of grade 316L according to an embodiment of the invention
  • Example 4 corresponds to niobium-containing micro-alloyed steel of grade 904L according to an embodiment of the invention.
  • Examples 1 to 4 differ from conventional grades through their niobium content. It is to be pointed out that the niobium concentration of the five alloys is much lower than the concentration that is required to obtain stabilisation of the steel by precipitation of carbon and nitrogen.
  • the niobium micro-alloy embodiments of the invention target refining of grain size after forging and not stabilisation
  • Reference 1 is a steel of same composition as in Example 1 but substantially devoid of niobium.
  • Reference 2 is a steel of same composition as Example 3 but substantially devoid of niobium.
  • Reference 3 is a steel of same composition as Example 4 but devoid of niobium.
  • the table above compares the mean grain size of steels according to Examples 1 to 4 and for the reference steels 1 to 3 under different heat treatments 1 to 4.
  • This mean size is advantageously measured via image analysis i.e. automatic process which interprets metallographic images in which the grain boundaries are evidenced.
  • Another possible technique is naked eye comparison of microstructure photos with standard images, to obtain a grain size number which is also representative of a mean value (e.g. number 10 corresponds to 10 ⁇ m and number 8 to 20 ⁇ m). The measured number is then converted to a mean grain size expressed in micrometres.
  • Treatment 1 corresponds to dynamic recrystallization.
  • Treatment 2 is annealing at 1100° C. for 30 min (static recrystallization).
  • Treatment 3 is annealing at 1100° C. for 5 hours (static recrystallization and grain growth).
  • Treatment 4 is annealing at 1100° C. for 20 hours (static recrystallization and grain growth).
  • the micro-alloyed steels exhibit a grain size that is reduced by at least one grain size number. It is therefore a significant reduction that is relevant with regard to ultrasonic permeability when the grain size number is close to zero which is the case for the very large forged parts in austenitic stainless steels.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Forging (AREA)
US14/775,704 2013-03-13 2014-03-07 Stainless steel for hot forging and hot forging method using said steel Abandoned US20160024626A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR1352241A FR3003271B1 (fr) 2013-03-13 2013-03-13 Acier inoxydable pour forgeage a chaud et procede de forgeage a chaud utilisant cet acier
FR1352241 2013-03-13
PCT/EP2014/054466 WO2014139890A1 (fr) 2013-03-13 2014-03-07 Acier inoxydable pour forgeage à chaud et procédé de forgeage à chaud utilisant cet acier

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EP (1) EP2971212A1 (fr)
JP (1) JP2016512573A (fr)
CN (1) CN105121689A (fr)
FR (1) FR3003271B1 (fr)
WO (1) WO2014139890A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10669601B2 (en) 2015-12-14 2020-06-02 Swagelok Company Highly alloyed stainless steel forgings made without solution anneal

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105543711B (zh) * 2015-12-22 2017-06-20 东北大学 抑制超级奥氏体不锈钢的铬和钼元素中心偏析的铸轧方法
CN106636951A (zh) * 2016-11-10 2017-05-10 合肥辰泰安全设备有限责任公司 一种水雾喷嘴用合金材料
CN110218943A (zh) * 2019-07-02 2019-09-10 珠海国合融创科技有限公司 一种奥氏体不锈钢及其制备方法
CN116536574A (zh) * 2023-03-24 2023-08-04 鞍钢股份有限公司 一种低温性能优异的奥氏体不锈钢及其制备方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264145A (en) * 1963-09-03 1966-08-02 United States Steel Corp Method of heat treating heavy alloy steel forgings
US20100034689A1 (en) * 2007-10-03 2010-02-11 Hiroyuki Hirata Austenitic stainless steel
US9347121B2 (en) * 2011-12-20 2016-05-24 Ati Properties, Inc. High strength, corrosion resistant austenitic alloys

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5940206B2 (ja) * 1979-02-14 1984-09-28 株式会社神戸製鋼所 熱間加工用オ−ステナイト系ステンレス鋼の製造方法
JPS58144420A (ja) * 1982-02-19 1983-08-27 Kawasaki Steel Corp オ−ステナイト系ステンレス大型鍛鋼の製造方法
JPS60200952A (ja) * 1984-03-26 1985-10-11 Kawasaki Steel Corp 大型厚肉オ−ステナイト系ステンレス鍛鋼
JPS61139653A (ja) * 1984-12-11 1986-06-26 Kawasaki Steel Corp 高温強度、延性のすぐれた厚肉オ−ステナイト系ステンレス鋼
JPS6280221A (ja) * 1985-10-03 1987-04-13 Kawasaki Steel Corp オ−ステナイト系ステンレス厚肉鍛鋼品の製造方法
JPS62224632A (ja) * 1986-03-26 1987-10-02 Sumitomo Metal Ind Ltd 高Ｓｉ二相ステンレス鋼の熱間鍛造法
JPH07316653A (ja) * 1994-05-19 1995-12-05 Nippon Steel Corp 極低温特性に優れたステンレス鋼厚板の製造方法
JPH11256283A (ja) * 1998-03-13 1999-09-21 Sumitomo Metal Ind Ltd 熱間加工性に優れたオーステナイト系ステンレス鋼
JP2000144253A (ja) * 1998-11-11 2000-05-26 Daido Steel Co Ltd 強度および耐食性の優れた大型鍛造品の製造方法
KR100351509B1 (ko) * 1999-10-05 2002-10-25 학교법인 포항공과대학교 절삭용 스테인리스강 및 그 가공방법
FR2832425B1 (fr) * 2001-11-16 2004-07-30 Usinor Alliage austentique pour tenue a chaud a coulabilite et transformation ameliorees
JP2003213379A (ja) * 2002-01-21 2003-07-30 Sumitomo Metal Ind Ltd 耐食性に優れたステンレス鋼
JP4424471B2 (ja) * 2003-01-29 2010-03-03 住友金属工業株式会社 オーステナイト系ステンレス鋼およびその製造方法
JP2008036698A (ja) * 2006-08-09 2008-02-21 Daido Steel Co Ltd オーステナイト系ステンレス鋼大型鍛造品の製造方法
US20090129967A1 (en) * 2007-11-09 2009-05-21 General Electric Company Forged austenitic stainless steel alloy components and method therefor
JP5396089B2 (ja) * 2009-01-15 2014-01-22 濱中ナット株式会社 熱間鍛造ステンレスナット

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264145A (en) * 1963-09-03 1966-08-02 United States Steel Corp Method of heat treating heavy alloy steel forgings
US20100034689A1 (en) * 2007-10-03 2010-02-11 Hiroyuki Hirata Austenitic stainless steel
US9347121B2 (en) * 2011-12-20 2016-05-24 Ati Properties, Inc. High strength, corrosion resistant austenitic alloys

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10669601B2 (en) 2015-12-14 2020-06-02 Swagelok Company Highly alloyed stainless steel forgings made without solution anneal

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EP2971212A1 (fr) 2016-01-20
WO2014139890A1 (fr) 2014-09-18
FR3003271B1 (fr) 2015-04-17
FR3003271A1 (fr) 2014-09-19
JP2016512573A (ja) 2016-04-28
CN105121689A (zh) 2015-12-02

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