EP0572246A1 - Forging and a method for its manufacture - Google Patents
Forging and a method for its manufacture Download PDFInfo
- Publication number
- EP0572246A1 EP0572246A1 EP19930304100 EP93304100A EP0572246A1 EP 0572246 A1 EP0572246 A1 EP 0572246A1 EP 19930304100 EP19930304100 EP 19930304100 EP 93304100 A EP93304100 A EP 93304100A EP 0572246 A1 EP0572246 A1 EP 0572246A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- weight
- percent
- forging
- fatigue strength
- billet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000005242 forging Methods 0.000 title claims abstract description 27
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 239000000463 material Substances 0.000 claims abstract description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract 6
- 229910052742 iron Inorganic materials 0.000 claims abstract 3
- 238000001816 cooling Methods 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- 239000002826 coolant Substances 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium(0) Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims 2
- 229910000831 Steel Inorganic materials 0.000 description 13
- 239000010959 steel Substances 0.000 description 13
- 239000000203 mixture Substances 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 230000003068 static Effects 0.000 description 4
- 229910000742 Microalloyed steel Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 229910000997 High-speed steel Inorganic materials 0.000 description 1
- 238000005279 austempering Methods 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- TWXTWZIUMCFMSG-UHFFFAOYSA-N nitride(3-) Chemical compound [N-3] TWXTWZIUMCFMSG-UHFFFAOYSA-N 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 230000000171 quenching Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
Abstract
For producing a forging with good fatigue strength the billet for the desired forging is made of a material which, in addition to iron, contains the following elements:
C from 0.2 to 0.6 percent by weight
Si from 1.25 to 2.0 percent by weight
Mn from 0.5 to 1.5 percent by weight
V from 0.04 to 0.2 percent by weight
S from 0 to 0.2 percent by weight
Cr from 0 to 0.5 percent by weight
Al from 0 to 0.1 percent by weight
N from 0 to 0.04 percent by weight
Nb from 0 to 0.1 percent by weight
Ti from 0 to 0.05 percent by weight.
The billet is forged at a temperature of more than 800°C. Subsequently, the billet, which has now become a forging, is cooled in air or gas substantially uniformly acting on the forging.
C from 0.2 to 0.6 percent by weight
Si from 1.25 to 2.0 percent by weight
Mn from 0.5 to 1.5 percent by weight
V from 0.04 to 0.2 percent by weight
S from 0 to 0.2 percent by weight
Cr from 0 to 0.5 percent by weight
Al from 0 to 0.1 percent by weight
N from 0 to 0.04 percent by weight
Nb from 0 to 0.1 percent by weight
Ti from 0 to 0.05 percent by weight.
The billet is forged at a temperature of more than 800°C. Subsequently, the billet, which has now become a forging, is cooled in air or gas substantially uniformly acting on the forging.
Description
- This invention relates to a method for producing a forging with good fatigue strength and to a forging having good fatigue strength.
- For machine elements, produced by hot forging, which become exposed to fatigue load, the fatigue strength Sv is most often a critical feature which determines the dimensions of the element. The problem is that the static strength of the element in question, for example its tensile strength Rm, has an affect on the machinability of the material. With regard to the total production cost of an element the optimum static tensile strength is about 1000 MPa. If the element has a static tensile strength essentially exceeding this value, the machinability of the material is poor in many cases causing, in particular, high speed steel tools to wear rapidly when machining the material resulting in unreasonably high tool costs. If the fatigue strength of an element can be increased without increasing its static strength, the element can be made more slender and high cutting costs can be avoided. Then the element will be lighter and the production costs will be lower, resulting in a rise in the value of the element and/or lower total production costs.
- The cold cropping of bars to produce forging billets, which precedes the forging of modern microalloyed steels, often causes a problem, in particular when the tensile strength in the rolling phase exceeds 900 MPa. In particular the cropping usually creates cracks on the shear surface of the cropped billet. If the fatigue strength of the final forging can be raised without raising the tensile strength of the bar blank, the alloying of the steel can be reduced, inter alia with regard to manganese. Then the tensile strength is reduced and at the same time the cold cropping properties are improved without any reduction of the fatigue strength of the final forged product. In this way the cold cutting difficulties can be eliminated and the alloying costs can be reduced.
- Forgings made of known microalloyed steels, in particular connecting rods, crankshafts, drive shafts and the like, must often be surface finished, generally by working the surface (particle blasting, rolling, etc.), or by surface hardening, in order to improve the fatigue strength. The combination of the steel composition according to the invention and the treatment according to the invention essentially reduces the necessity of surface treatment for the type of products referred to, thereby reducing their production costs.
- The object of the invention is to produce a forging with a high fatigue strength without the above-described technical drawbacks. At the same time the advantages mentioned above are achieved. The object of the invention is obtained by the method of claim 1 and the forging of claims 6 and 7.
- Alloyed steels resembling the alloyed steel of the forging according to the invention have been used before, inter alia as raw material for steel springs and different fastening elements, as described in the Finnish laid open publication FI 48204. The main difference between the forging according to the invention and the known springs and fastening elements is that, according to the invention, the microstructure will be mostly (typically to more than 90 percent) ferritic-perlitic, which is obtained by air cooling, while the microstructure of the elements described in FI 48204 is martensite or bainite for the greatest part, which is obtained by quenching and tempering or austempering.
- According to the method of the invention the billets are hot forged at a temperature of more than 800°C and after that they are allowed to cool in air. This treatment is known per se as a treatment method for microalloyed steels for the purpose of eliminating a separate quench and temper treatment in order to reduce the production costs. In the case of the invention the treatment result is different. The high silicon content provides an improved fatigue strength. It is assumed that this is caused by the fact that small amounts of residual austenite are formed which, under fatigue stress, turn into martensite. Thereby a so-called cyclic work hardening takes place, which increases the fatigue strength.
- Novel in the invention is the combination of a steel according to the invention, containing a high degree of silicon, and a working method generally used in the production of other microalloyed steel forgings. This results, for the reasons explained above, in a product with a fatigue strength that is essentially better than in previously known microalloyed steel products.
- A silicon content higher than normal in air-cooled microalloyed steels is known from DE-A-3009443. The invention differs from this, firstly in that the silicon content is higher, and secondly, in that the object is to improve the fatigue strength, whereas the object of the known technique is to improve the notch toughness, not the fatigue strength.
- It is of advantage for an element according to the invention that its production process includes, before hot forging, heating to such a high temperature that the vanadium carbonitrides of the element dissolve. This improves the strength of the element so that it is usually near the optimum value mentioned on the first page of this specification, which also is of advantage with respect to the fatigue strength.
- By reducing the nitrogen content of the material to at the most 0.012 percent by weight, or the titanium content to at the most 0.01 percent by weight, the advantage is achieved that large nitride particles harmful for the fatigue strength, will not be formed. This is ensured, in particular, if the continuous casting method is used in the manufacturing process of the material.
- In order to obtain better mechanical features the cooling of the forging can be effected by using flowing air as coolant, preferably air moistened, for instance by water spray. It is of advantage to use this kind of forced cooling when the temperature of the element is above 600°C. The forced cooling causes the forging to obtain a sufficient strength without any negative influence on its toughness. This is because forced cooling results in a finer micro structure of the element. The grain size becomes smaller and the interlamellar spacing of the perlite remains small, whereby the strength is improved but the toughness remains unaltered.
- The following test results show the improvement of the fatigue strength achieved by the combination of the method and the steel composition according to the invention.
- The fatigue strength Sv was determined in a rotating bending test, load alternations 10 million revolutions. The ultimate tensile strength Rm influences the fatigue strength, which means that the ratio of fatigue strength and tensile strength must be observed. Compared to modern reference steels the improvement in the fatigue strength to tensile strength ratio for steels produced according to the invention is from about 10 to 30%.
- The invention is not limited to the disclosed examples and modifications are feasible within the scope of the appended claims.
Claims (7)
- A method for producing a forging with good fatigue strength, characterised by the combination that the billet for the desired forging is made of a material which, in addition to iron, contains the following elements:
C from 0.2 to 0.6 percent by weight
Si from 1.25 to 2.0 percent by weight
Mn from 0.5 to 1.5 percent by weight
V from 0.04 to 0.2 percent by weight
S from 0 to 0.2 percent by weight
Cr from 0 to 0.5 percent by weight
Al from 0 to 0.1 percent by weight
N from 0 to 0.04 percent by weight
Nb from 0 to 0.1 percent by weight
Ti from 0 to 0.05 percent by weight,
that the billet is forged at a temperature of more than 800°C and that the forging so formed is subsequently cooled in air or gas substantially uniformly acting on the forging. - A method according to claim 1, characterised in that the billet before the hot forging is heated to a temperature, where its vanadium carbonitrides dissolve.
- A method according to claim 1 or 2, characterised in that the nitrogen content of the material is no more than 0.012 percent by weight.
- A method according to claim 1, 2 or 3, characterised in that the titanium content of the material is no more than 0.01 per cent by weight.
- A method according to any of the preceding claims, characterised in that in the cooling of the forging, at least when its temperature is above 600°C, dry or humid flowing air or gas is used as a coolant.
- A forging made by the method of any one of claims 1 to 5.
- A forging with good fatigue strength, characterised in that it is made of a material which, in addition to iron, contains the following elements:
C from 0.2 to 0.6 percent by weight
Si from 1.25 to 2.0 percent by weight
Mn from 0.5 to 1.5 percent by weight
V from 0.04 to 0.2 percent by weight
S from 0 to 0.2 percent by weight
Cr from 0 to 0.5 percent by weight
Al from 0 to 0.1 percent by weight
N from 0 to 0.04 percent by weight
Nb from 0 to 0.1 percent by weight
Ti from 0 to 0.05 percent by weight,
and in that the microstructure of the forging is mostly ferritic-perlitic.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI922461A FI922461A (en) | 1992-05-29 | 1992-05-29 | SMIDESSTYCKE OCH DESS FRAMSTAELLNINGSFOERFARANDE |
| FI922461 | 1992-05-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0572246A1 true EP0572246A1 (en) | 1993-12-01 |
| EP0572246B1 EP0572246B1 (en) | 1997-01-15 |
Family
ID=8535372
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19930304100 Expired - Lifetime EP0572246B1 (en) | 1992-05-29 | 1993-05-26 | Forging and a method for its manufacture |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0572246B1 (en) |
| AT (1) | AT147799T (en) |
| DE (1) | DE69307393T2 (en) |
| FI (1) | FI922461A (en) |
| NO (1) | NO931961D0 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0798059A1 (en) * | 1996-03-29 | 1997-10-01 | Ascoforge Safe | Method of production of a blank for a forged connecting rod |
| ES2128240A1 (en) * | 1996-07-26 | 1999-05-01 | Gsb Grupo Siderurgico Vasco S | Process for the manufacture of microalloy steels |
| EP0924440A2 (en) * | 1997-11-21 | 1999-06-23 | Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 | Forged connecting rod of carbon steel for piston engines with breaking separated bearing sap |
| EP1700925A1 (en) * | 2005-03-09 | 2006-09-13 | Imatra Steel Oy Ab | High-strength air cooled steel alloy, manufacturing method and hot worked product |
| ITTO20090451A1 (en) * | 2009-06-12 | 2010-12-13 | F A C E M S P A | PROCEDURE FOR THE PRODUCTION OF A CEMENTATION STEEL PIECE, BASED ON HOT MOLDING FOLLOWED BY CONDITIONED COOLING AND SUB-CRITICAL ANNEALING, AND ITS RELATIVE SYSTEM |
| JP2015183253A (en) * | 2014-03-25 | 2015-10-22 | 愛知製鋼株式会社 | Non-conditioned steel for saving v type hot forging excellent in machinability and fatigue strength and having small hardness variation, hot forged component manufactured by using the steel and manufacturing method therefor |
| JP2017171977A (en) * | 2016-03-23 | 2017-09-28 | 愛知製鋼株式会社 | Crankshaft, manufacturing method therefor, and steel for crankshaft |
| WO2019088190A1 (en) * | 2017-10-31 | 2019-05-09 | 日本製鉄株式会社 | Hot forged steel |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102019123334A1 (en) | 2019-08-30 | 2021-03-04 | Mannesmann Precision Tubes Gmbh | Steel material for a drive shaft, method for producing a drive shaft from this steel material and drive shaft therefrom |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3173782A (en) * | 1962-06-13 | 1965-03-16 | Bethlehem Steel Corp | Vanadium nitrogen steel |
| SU301371A1 (en) * | 1969-06-04 | 1971-04-21 | В. В. Рунов, К. Шепел козский , В. М. Семенов Научно исследовательский институт автотракторных материалов | SPRING STEEL |
| DE2210915A1 (en) * | 1972-03-07 | 1973-09-20 | Hoesch Werke Ag | Evaporater tubes - by heat treating welded silicon manganese steel strip, for sugar mfr |
| GB1441695A (en) * | 1974-03-04 | 1976-07-07 | Towmotor Corp | High strength steel |
| SU522264A1 (en) * | 1975-03-20 | 1976-07-25 | Ордена Трудового Красного Знамени Центральный Научно-Исследовательский Институт Черной Металлургии Им.И.П.Бардина | Structural steel |
| EP0035681A1 (en) * | 1980-03-12 | 1981-09-16 | Thyssen Edelstahlwerke AG | Use of a steel having high strength and toughness |
| DE3124977A1 (en) * | 1980-06-26 | 1982-04-29 | Kabushiki Kaisha Kobe Seiko Sho, Kobe | Spring steel for vehicles |
-
1992
- 1992-05-29 FI FI922461A patent/FI922461A/en not_active Application Discontinuation
-
1993
- 1993-05-26 DE DE1993607393 patent/DE69307393T2/en not_active Expired - Fee Related
- 1993-05-26 EP EP19930304100 patent/EP0572246B1/en not_active Expired - Lifetime
- 1993-05-26 AT AT93304100T patent/AT147799T/en not_active IP Right Cessation
- 1993-05-28 NO NO931961A patent/NO931961D0/en unknown
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3173782A (en) * | 1962-06-13 | 1965-03-16 | Bethlehem Steel Corp | Vanadium nitrogen steel |
| SU301371A1 (en) * | 1969-06-04 | 1971-04-21 | В. В. Рунов, К. Шепел козский , В. М. Семенов Научно исследовательский институт автотракторных материалов | SPRING STEEL |
| DE2210915A1 (en) * | 1972-03-07 | 1973-09-20 | Hoesch Werke Ag | Evaporater tubes - by heat treating welded silicon manganese steel strip, for sugar mfr |
| GB1441695A (en) * | 1974-03-04 | 1976-07-07 | Towmotor Corp | High strength steel |
| SU522264A1 (en) * | 1975-03-20 | 1976-07-25 | Ордена Трудового Красного Знамени Центральный Научно-Исследовательский Институт Черной Металлургии Им.И.П.Бардина | Structural steel |
| EP0035681A1 (en) * | 1980-03-12 | 1981-09-16 | Thyssen Edelstahlwerke AG | Use of a steel having high strength and toughness |
| DE3124977A1 (en) * | 1980-06-26 | 1982-04-29 | Kabushiki Kaisha Kobe Seiko Sho, Kobe | Spring steel for vehicles |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0798059A1 (en) * | 1996-03-29 | 1997-10-01 | Ascoforge Safe | Method of production of a blank for a forged connecting rod |
| FR2746683A1 (en) * | 1996-03-29 | 1997-10-03 | Ascoforge Safe | METHOD FOR MANUFACTURING FORGED ROD BLANK |
| US5878491A (en) * | 1996-03-29 | 1999-03-09 | Ascoforge Safe | Process for the manufacture of a forged connecting rod |
| ES2128240A1 (en) * | 1996-07-26 | 1999-05-01 | Gsb Grupo Siderurgico Vasco S | Process for the manufacture of microalloy steels |
| EP0924440A2 (en) * | 1997-11-21 | 1999-06-23 | Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 | Forged connecting rod of carbon steel for piston engines with breaking separated bearing sap |
| EP0924440A3 (en) * | 1997-11-21 | 2000-04-19 | Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 | Forged connecting rod of carbon steel for piston engines with breaking separated bearing sap |
| EP1700925A1 (en) * | 2005-03-09 | 2006-09-13 | Imatra Steel Oy Ab | High-strength air cooled steel alloy, manufacturing method and hot worked product |
| ITTO20090451A1 (en) * | 2009-06-12 | 2010-12-13 | F A C E M S P A | PROCEDURE FOR THE PRODUCTION OF A CEMENTATION STEEL PIECE, BASED ON HOT MOLDING FOLLOWED BY CONDITIONED COOLING AND SUB-CRITICAL ANNEALING, AND ITS RELATIVE SYSTEM |
| JP2015183253A (en) * | 2014-03-25 | 2015-10-22 | 愛知製鋼株式会社 | Non-conditioned steel for saving v type hot forging excellent in machinability and fatigue strength and having small hardness variation, hot forged component manufactured by using the steel and manufacturing method therefor |
| JP2017171977A (en) * | 2016-03-23 | 2017-09-28 | 愛知製鋼株式会社 | Crankshaft, manufacturing method therefor, and steel for crankshaft |
| WO2019088190A1 (en) * | 2017-10-31 | 2019-05-09 | 日本製鉄株式会社 | Hot forged steel |
| CN111295457A (en) * | 2017-10-31 | 2020-06-16 | 日本制铁株式会社 | Hot forged steel material |
| JPWO2019088190A1 (en) * | 2017-10-31 | 2020-11-12 | 日本製鉄株式会社 | Hot forged steel |
Also Published As
| Publication number | Publication date |
|---|---|
| FI922461A0 (en) | 1992-05-29 |
| AT147799T (en) | 1997-02-15 |
| NO931961D0 (en) | 1993-05-28 |
| DE69307393T2 (en) | 1997-05-15 |
| EP0572246B1 (en) | 1997-01-15 |
| FI922461A (en) | 1993-11-30 |
| DE69307393D1 (en) | 1997-02-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2357260B1 (en) | Case hardening steel, carburized component, and manufacturing method of case hardening steel | |
| EP1602742B1 (en) | High-strength steel for large-scaled forging, and crankshaft | |
| KR100939462B1 (en) | Hot forged products excellent in fatigue strength, process for production thereof, and machine structural parts | |
| US5252153A (en) | Process for producing steel bar wire rod for cold working | |
| EP3623485B1 (en) | Method for producing an ausferritic steel, austempered during continuous cooling followed by annealing | |
| JPH10235447A (en) | Manufacture of ferrite plus pearlite type non-heattreated steel forged product having high toughness and high yield strength | |
| JP4299744B2 (en) | Hot rolled wire rod for cold forging and method for producing the same | |
| EP0572246B1 (en) | Forging and a method for its manufacture | |
| US7217329B2 (en) | Carbon-titanium steel rail | |
| CN113862576A (en) | Non-quenched and tempered steel, crankshaft and production method thereof | |
| JP4393344B2 (en) | Manufacturing method of case hardening steel with excellent cold workability and grain coarsening resistance | |
| US4806178A (en) | Non-heat refined steel bar having improved toughness | |
| JP3677972B2 (en) | Method for producing steel material for cold forging containing boron | |
| JP3357264B2 (en) | Manufacturing method of non-tempered steel bar for high toughness hot forging | |
| JPH08170146A (en) | Nitrided and non-heattreated steel for forming and nitrided and non-heattreated forged product | |
| JPH0643605B2 (en) | Manufacturing method of non-heat treated steel for hot forging | |
| KR950009168B1 (en) | Making method of non-heat-treatment steel with hot forging | |
| JPH0762204B2 (en) | Manufacturing method of high-toughness non-heat treated steel for hot forging and its steel bars and parts | |
| JP4006857B2 (en) | Cold forging steel for induction hardening, machine structural parts and manufacturing method thereof | |
| JPH05339676A (en) | Steel for machine structure excellent in cold workability and its manufacture | |
| FI95050C (en) | Forging piece and its manufacturing process | |
| EP1553197B1 (en) | Steel material for mechanical structure excellent in suitability for rolling, quenching crack resistance, and torsional property and drive shaft | |
| JP3931400B2 (en) | Method for producing boron steel | |
| KR100415653B1 (en) | Method for manufacturing micro-alloyed steel sheet having high strength and high ductility for hot-forging | |
| JP3762543B2 (en) | Manufacturing method of non-tempered steel for hot forging and non-tempered hot forged product and hot forged non-tempered product |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT CH DE ES FR GB IT LI SE |
|
| 17P | Request for examination filed |
Effective date: 19931113 |
|
| GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
| 17Q | First examination report despatched |
Effective date: 19960429 |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT CH DE ES FR GB IT LI SE |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Effective date: 19970115 Ref country code: IT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRE;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.SCRIBED TIME-LIMIT Effective date: 19970115 Ref country code: ES Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY Effective date: 19970115 Ref country code: CH Effective date: 19970115 Ref country code: AT Effective date: 19970115 |
|
| REF | Corresponds to: |
Ref document number: 147799 Country of ref document: AT Date of ref document: 19970215 Kind code of ref document: T |
|
| REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
| REF | Corresponds to: |
Ref document number: 69307393 Country of ref document: DE Date of ref document: 19970227 |
|
| ET | Fr: translation filed | ||
| REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
| PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
| 26N | No opposition filed | ||
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19980408 Year of fee payment: 6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 19980416 Year of fee payment: 6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19980417 Year of fee payment: 6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19980429 Year of fee payment: 6 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19990526 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19990527 |
|
| GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 19990526 |
|
| EUG | Se: european patent has lapsed |
Ref document number: 93304100.6 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20000131 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20000301 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |