CA1084823A - Treatment of rolled steel products - Google Patents
Treatment of rolled steel productsInfo
- Publication number
- CA1084823A CA1084823A CA262,319A CA262319A CA1084823A CA 1084823 A CA1084823 A CA 1084823A CA 262319 A CA262319 A CA 262319A CA 1084823 A CA1084823 A CA 1084823A
- Authority
- CA
- Canada
- Prior art keywords
- product
- cooling
- fluid
- temperature
- quenching
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/02—Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A rolled steel product emerging from a hot rolling mill is cooled by means of a fluid so as to produce martensitic and/or bainitic quenching of the surface layer of all or part of the product. The non-quenched portion remains at a temperature sufficient to cause tempering of the martensite and/or bainite in the surface layer to take place during subsequent air cooling.
According to the invention, the maximum temperature of the tempered surface of the product after quenching is 600 to 730°C. The method is of utility in treating concrete-reinforcing rod, wire rod, steel sheet, and steel sections.
A rolled steel product emerging from a hot rolling mill is cooled by means of a fluid so as to produce martensitic and/or bainitic quenching of the surface layer of all or part of the product. The non-quenched portion remains at a temperature sufficient to cause tempering of the martensite and/or bainite in the surface layer to take place during subsequent air cooling.
According to the invention, the maximum temperature of the tempered surface of the product after quenching is 600 to 730°C. The method is of utility in treating concrete-reinforcing rod, wire rod, steel sheet, and steel sections.
Description
8;~
The presen-t inverl,ioll re]ates to a metho~ oi trea~;iDg rolled steel. produc-ts~ the method bei.ng applicable to concrete~reililorci.ng rod, wire rod, or bars o-f circular or non-circular cross-section, all these being referred ~o as "rods" below, and being appli.cable -to sections co~stituted by one web or by seve:ral in-tegral webs, the term "sections" also being used.in this specification to incl.ude rolled p.roducts such as sheet bars and sheets.
The main quali-ties required by users of rolled steel products, among others, are as high as possible a ].imit of elastici-ty for the grade of steel used, as well as (depending on the circ-~mstances and the use for which the ~ products is intended) sa-tisfactory fatigue strength, : ductility, weldability, or drawability.
~o this end, we have already suggested subjecting a rolled product emerging from the finishing s-tand of the rolling mill to cooling by means of a fluid so as to produce martensitic and/or bainitic quenching of the sur~ace layer of all or part of the product. Moreover, we have already suggested that i-t is desirable that, at the outlet of the fluid cooling zone, the non-quenched portion of the rolled product is at a temperat-ure sufficient to permit, during subsequent air cooling~ tempering of the surface layer of martensite and/or bainite to take place.
~he cooling fluid employed for carrying out the method is usually water with or without conventi.onal additives, or aqueous of mineral salts, for example. ~he ~t,,~
fl.uid mc-~y be a mist, for example obtained by s~sp*llding water in a gas, or it may be a gas, such ac s-team (wa-ter vapour).
~rom -the practical view poi.nt, desired cooling of the rol].ed products depends on the cooling d.evices used, alld on suita.ble choice of the leng-th and the flow rate characteristics of the cooling means.
The present invention relates particularly to the determination of the opera-ting conditions of quenching and ~ 10 self--tempering of the surface layer of the rolled products, ,~ as referred to above.
In practice, the method in question is performed in an install.ation whose main elements (finishing stand of -the rolling mill and air cooling region) are located at predetermined fixed positions, this determining the available ~' length Or the quenching zone. It is only rarely that it is possible to adapt the whole installation to the possible requirements of the method.
In general, the speed and the temperature of the rolled , 20 products at the outlet of the last stand of the rolling mill are data of the process too. On the other hand, the method is applicable to one product at a time, the dimensions of the product being known as well as the composition of the steel, and thus its CCl (continuous cooling transforma-tion) diagram. Knowing this diagram, it is possible to determine a nu~ber of conditions governing the treatment of the product in question, such as the temperature at which formation of martensite occurs and the maximum time available io8~Z3 fo.r performing su:rface quenching, particularly to -the desired depth.
~o determine the cha:racteristi.cs of the cooling devices, such as the cooli.ng ram~s or sprays, and the flow rates of the fluid to be applied by means of such devices, it is possible to draw curves of the temperature gradien-ts in the core and the skin of the rolled produ.ct subjected to the treatment in question, and thus the amoun-t of heat to be removed may be determincd. From known da-ta of the treatment installation and the product to be -treated and by estimating the cooling requirements to be me-t, it is then possible to de-termine the characteristics of the cooiing devices and the flow rates of the fluid applied by the devices.
; 15 The present invention relates to a method which is particularly suitable for subjecting the products to martensitic and/or bainitic surface quenching followed by self-tempering, and adapted to ensure ready and effective course of the treatment. The method comprises determining an important datum to choose the conditions for carrying out the treatment.
The method is based on the observation of the evolution of the skin temperature of the product starting from the end of the martensitic and/or bainitic quenching: during the period following quenching, the skin temperature rises (the temperature at the core continuously decreases af-ter the product has emerged from the last stand of the rolling mill). The skin temperature and the core temperature in a 1~48Z3 gi.ven crosx-section, developing independently of one anothcr~ converge towa.rds a point called the "equalizatior.
tempelat-lre" from wh^re the -two curves contiIlue substc~ntially parallel to one another. Ihe "equaliza-tion temperature" is readily dete:rmined since it is the temperat-ure after which the skin -temperature starts : decreasing again: it is thus amaximum in the curve of the skin temperature agains-t time.
It should be noted that th.e e~ualization temperature is not necessarily that prevailing throughout the cross-` section, because a difference of many degrees, e.g 40 to 50C, might exis-t between -the skin and the core.
; ~'he method of treating rolled steel products according to the present invention is characterised in that, as a convergence point for the curves of the course of the temperature at the skin after quenching and the temperatures at the core during cooling, one chooses a tempera-ture in the range of 600C to 730C.
According to a particular way of carrying out the - 20 method of the present invention, one chooses the level of the equalization temperature, in the range 600 to 730C, from a dlagram showing the course of the elastic limit as a function of the equalization temperature. We have unexpectedly found tha-t a direct relationship exists between the equalization temperature and the mechar.ical properties of the product subjected to surface quenching and self-tempering as described above, whatever the grade of the steel, even in the presence of a]loying elements (e.g. ~b).
_ ~ _ 3Z,3 - ~he de<,i.red. col~ver.genc:e of the temperat;-u~cs a-'- theskin a~te:r quenc~ing and a-t the core during cooling i.s obtair~.ed by suitably choosing -the cooling devices and -the flow rates of the cooling fluid.
,.
; 5 F~MPIE
Steel rod was treated, having a diameter of 14 mm and containing, by weight:
carbon 0.1 5%
manganese 0.97~o silicon 0~05%O
~he temperature at the end o~ the rolling operation was 950C. (~he untreated rod, i.e. air cooled without surface quenching and self-tempering, had an elastic limit of 33 kg/mm .) When treated according to the method in accordance with the present invention, the rod had an elastic limit of 46 kg/mm af-ter treatment in conditions such that the equalization temperature was 680C, and had an elastic limit of 49 kg/mm2 when the equalization temperature was 650C.
A particularly advantageous modification of the method of the invention is easy to carry out, simple, and effective.
According to such modifications, one determines the surface temperature to be presented by the said rolled product at a given place along its path so that the skin temperature after quenching and the temperature of the non-quenched part during cooling converge to a value ranging from 600C
to 730C, one measures the surface temperature of the product at the said given place, and one adjusts the cooling 4E~Z3 conditions in the insta]..lation so as to ~nainta.in the sllrface temeratl~.re oi -the product in a range sat:isfyirlg the conditlons for convergence of the temperatures.
Moreover, according to this variant, one determines the surface temperatuxe the rolled pxod.uct has to possess at the said given place, while taking into account, in particular, the dimensions of -the rolled product and the dura-tion of dwelling of the product in the quenching devices.
` 10 ~urthermore, one preferably chooses as the place where the surface temperature of the rolled produc-t is ; me&sured, a region located at the inlet of a still-air cooling region.
~inally, it has been found to be advantageous to adjust the cooling conditions of the rolled product by regulating ~` the flow rate of the fluid in the cooling devices and/or the length oi` the cooling ra p.s or sprays.
:~
~ 6 --
The presen-t inverl,ioll re]ates to a metho~ oi trea~;iDg rolled steel. produc-ts~ the method bei.ng applicable to concrete~reililorci.ng rod, wire rod, or bars o-f circular or non-circular cross-section, all these being referred ~o as "rods" below, and being appli.cable -to sections co~stituted by one web or by seve:ral in-tegral webs, the term "sections" also being used.in this specification to incl.ude rolled p.roducts such as sheet bars and sheets.
The main quali-ties required by users of rolled steel products, among others, are as high as possible a ].imit of elastici-ty for the grade of steel used, as well as (depending on the circ-~mstances and the use for which the ~ products is intended) sa-tisfactory fatigue strength, : ductility, weldability, or drawability.
~o this end, we have already suggested subjecting a rolled product emerging from the finishing s-tand of the rolling mill to cooling by means of a fluid so as to produce martensitic and/or bainitic quenching of the sur~ace layer of all or part of the product. Moreover, we have already suggested that i-t is desirable that, at the outlet of the fluid cooling zone, the non-quenched portion of the rolled product is at a temperat-ure sufficient to permit, during subsequent air cooling~ tempering of the surface layer of martensite and/or bainite to take place.
~he cooling fluid employed for carrying out the method is usually water with or without conventi.onal additives, or aqueous of mineral salts, for example. ~he ~t,,~
fl.uid mc-~y be a mist, for example obtained by s~sp*llding water in a gas, or it may be a gas, such ac s-team (wa-ter vapour).
~rom -the practical view poi.nt, desired cooling of the rol].ed products depends on the cooling d.evices used, alld on suita.ble choice of the leng-th and the flow rate characteristics of the cooling means.
The present invention relates particularly to the determination of the opera-ting conditions of quenching and ~ 10 self--tempering of the surface layer of the rolled products, ,~ as referred to above.
In practice, the method in question is performed in an install.ation whose main elements (finishing stand of -the rolling mill and air cooling region) are located at predetermined fixed positions, this determining the available ~' length Or the quenching zone. It is only rarely that it is possible to adapt the whole installation to the possible requirements of the method.
In general, the speed and the temperature of the rolled , 20 products at the outlet of the last stand of the rolling mill are data of the process too. On the other hand, the method is applicable to one product at a time, the dimensions of the product being known as well as the composition of the steel, and thus its CCl (continuous cooling transforma-tion) diagram. Knowing this diagram, it is possible to determine a nu~ber of conditions governing the treatment of the product in question, such as the temperature at which formation of martensite occurs and the maximum time available io8~Z3 fo.r performing su:rface quenching, particularly to -the desired depth.
~o determine the cha:racteristi.cs of the cooling devices, such as the cooli.ng ram~s or sprays, and the flow rates of the fluid to be applied by means of such devices, it is possible to draw curves of the temperature gradien-ts in the core and the skin of the rolled produ.ct subjected to the treatment in question, and thus the amoun-t of heat to be removed may be determincd. From known da-ta of the treatment installation and the product to be -treated and by estimating the cooling requirements to be me-t, it is then possible to de-termine the characteristics of the cooiing devices and the flow rates of the fluid applied by the devices.
; 15 The present invention relates to a method which is particularly suitable for subjecting the products to martensitic and/or bainitic surface quenching followed by self-tempering, and adapted to ensure ready and effective course of the treatment. The method comprises determining an important datum to choose the conditions for carrying out the treatment.
The method is based on the observation of the evolution of the skin temperature of the product starting from the end of the martensitic and/or bainitic quenching: during the period following quenching, the skin temperature rises (the temperature at the core continuously decreases af-ter the product has emerged from the last stand of the rolling mill). The skin temperature and the core temperature in a 1~48Z3 gi.ven crosx-section, developing independently of one anothcr~ converge towa.rds a point called the "equalizatior.
tempelat-lre" from wh^re the -two curves contiIlue substc~ntially parallel to one another. Ihe "equaliza-tion temperature" is readily dete:rmined since it is the temperat-ure after which the skin -temperature starts : decreasing again: it is thus amaximum in the curve of the skin temperature agains-t time.
It should be noted that th.e e~ualization temperature is not necessarily that prevailing throughout the cross-` section, because a difference of many degrees, e.g 40 to 50C, might exis-t between -the skin and the core.
; ~'he method of treating rolled steel products according to the present invention is characterised in that, as a convergence point for the curves of the course of the temperature at the skin after quenching and the temperatures at the core during cooling, one chooses a tempera-ture in the range of 600C to 730C.
According to a particular way of carrying out the - 20 method of the present invention, one chooses the level of the equalization temperature, in the range 600 to 730C, from a dlagram showing the course of the elastic limit as a function of the equalization temperature. We have unexpectedly found tha-t a direct relationship exists between the equalization temperature and the mechar.ical properties of the product subjected to surface quenching and self-tempering as described above, whatever the grade of the steel, even in the presence of a]loying elements (e.g. ~b).
_ ~ _ 3Z,3 - ~he de<,i.red. col~ver.genc:e of the temperat;-u~cs a-'- theskin a~te:r quenc~ing and a-t the core during cooling i.s obtair~.ed by suitably choosing -the cooling devices and -the flow rates of the cooling fluid.
,.
; 5 F~MPIE
Steel rod was treated, having a diameter of 14 mm and containing, by weight:
carbon 0.1 5%
manganese 0.97~o silicon 0~05%O
~he temperature at the end o~ the rolling operation was 950C. (~he untreated rod, i.e. air cooled without surface quenching and self-tempering, had an elastic limit of 33 kg/mm .) When treated according to the method in accordance with the present invention, the rod had an elastic limit of 46 kg/mm af-ter treatment in conditions such that the equalization temperature was 680C, and had an elastic limit of 49 kg/mm2 when the equalization temperature was 650C.
A particularly advantageous modification of the method of the invention is easy to carry out, simple, and effective.
According to such modifications, one determines the surface temperature to be presented by the said rolled product at a given place along its path so that the skin temperature after quenching and the temperature of the non-quenched part during cooling converge to a value ranging from 600C
to 730C, one measures the surface temperature of the product at the said given place, and one adjusts the cooling 4E~Z3 conditions in the insta]..lation so as to ~nainta.in the sllrface temeratl~.re oi -the product in a range sat:isfyirlg the conditlons for convergence of the temperatures.
Moreover, according to this variant, one determines the surface temperatuxe the rolled pxod.uct has to possess at the said given place, while taking into account, in particular, the dimensions of -the rolled product and the dura-tion of dwelling of the product in the quenching devices.
` 10 ~urthermore, one preferably chooses as the place where the surface temperature of the rolled produc-t is ; me&sured, a region located at the inlet of a still-air cooling region.
~inally, it has been found to be advantageous to adjust the cooling conditions of the rolled product by regulating ~` the flow rate of the fluid in the cooling devices and/or the length oi` the cooling ra p.s or sprays.
:~
~ 6 --
Claims (6)
1. A method of treating a rolled steel product emerging from a hot rolling mill, the method comprising cooling the product by means of a fluid so as to produce martensitic and/or bainitic quenching of the surface layer of all or part of the product, the non-quenched portion of the rolled product remaining at a temperature sufficient to cause tempering of the surface layer of martensite and/or bainite to take place during subsequent air cooling, in which method the maximum temperature of the tempered surface of the product after quenching is 600 to 73°C.
2. A method as claimed in claim 1, including selecting the said maximum temperature from a predetermined diagram showing the elastic limit of the product as a function of the said maximum temperature.
3. A method as claimed in claim 1, including determining the surface temperature range to be presented by the rolled product at a given place if the said maximum temperature is to be 600 to 730°C, measuring the actual surface temperature of the product at the said given place, and regulating the conditions of cooling by means of the fluid so as to maintain the actual surface temperature in the said surface temperature range.
4. A method as claimed in claim 3, in which the determination of the said surface temperature range takes into account the dimensions of the rolled product and the duration of cooling by means of the fluid.
5. A method as claimed in claim 3, in which the said given place is located at the inlet of a still-air cooling region.
6. A method as claimed in claim 3, in which the cooling conditions are controlled by regulating the flow rate of the cooling fluid and/or the length of the cooling path.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE6/45192 | 1975-09-30 | ||
| BE6045192A BE834059A (en) | 1975-09-30 | 1975-09-30 | PROCESS FOR TREATING LAMINATED STEEL PRODUCTS |
| BE6045591A BE843939A (en) | 1976-07-08 | 1976-07-08 | IMPROVEMENT IN QUENCHING AND SELF-REVENUE TREATMENT OF ROLLED STEEL PRODUCTS |
| BE6/45591 | 1976-07-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1084823A true CA1084823A (en) | 1980-09-02 |
Family
ID=25662109
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA262,319A Expired CA1084823A (en) | 1975-09-30 | 1976-09-29 | Treatment of rolled steel products |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5260215A (en) |
| AT (1) | AT370775B (en) |
| BR (1) | BR7606444A (en) |
| CA (1) | CA1084823A (en) |
| DE (1) | DE2643572A1 (en) |
| ES (1) | ES451966A1 (en) |
| GB (1) | GB1493230A (en) |
| LU (1) | LU75908A1 (en) |
| MX (1) | MX143817A (en) |
| NL (1) | NL7610472A (en) |
| SE (1) | SE430901B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2820323A1 (en) * | 1977-05-13 | 1978-11-23 | Arbed | METHOD FOR MANUFACTURING STEEL PROFILES WITH IMPROVED QUALITY |
| GB1552250A (en) * | 1977-12-20 | 1979-09-12 | British Steel Corp | Controlled quenching of hot rolled steel rod or bar |
| LU82858A1 (en) * | 1980-10-16 | 1982-05-10 | Arbed | PROCESS FOR THE MANUFACTURE OF STEEL LAMINES HAVING GOOD WELDABILITY, HIGH ELASTICITY LIMIT AND RESILIENCE AT VERY LOW TEMPERATURES |
| CH681603A5 (en) * | 1984-05-30 | 1993-04-30 | Von Roll Ag | |
| DE3431008C2 (en) * | 1984-08-23 | 1986-10-16 | Dyckerhoff & Widmann AG, 8000 München | Heat treatment of hot rolled bars or wires |
| DE3628264A1 (en) * | 1986-08-20 | 1988-02-25 | Man Nutzfahrzeuge Gmbh | Process for the manufacture of components from steel of high strength with at the same time high toughness, which retain these properties even after hot-forming |
| NL1007739C2 (en) | 1997-12-08 | 1999-06-09 | Hoogovens Staal Bv | Method and device for manufacturing a high strength steel strip. |
| CN106893827B (en) * | 2017-02-27 | 2018-08-07 | 鞍钢集团工程技术有限公司 | A kind of slab and special heavy plate quenching assay small rail car |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5115804B2 (en) * | 1971-12-06 | 1976-05-19 | ||
| DE2353034B2 (en) * | 1972-10-31 | 1980-03-13 | Centre De Recherches Metallurgiques- Centrum Voor Research In De Metallurgie, Bruessel | Process for improving the mechanical strength values of rolled steel products |
| NL170159C (en) * | 1973-06-04 | 1982-10-01 | Estel Hoogovens Bv | METHOD FOR MANUFACTURING WELDABLE LOW CARBON STEEL MATERIAL BY CONTROLLED COOLING |
-
1976
- 1976-09-21 NL NL7610472A patent/NL7610472A/en active Search and Examination
- 1976-09-28 DE DE19762643572 patent/DE2643572A1/en not_active Ceased
- 1976-09-28 BR BR7606444A patent/BR7606444A/en unknown
- 1976-09-28 SE SE7610749A patent/SE430901B/en unknown
- 1976-09-29 LU LU75908A patent/LU75908A1/xx unknown
- 1976-09-29 MX MX16648476A patent/MX143817A/en unknown
- 1976-09-29 JP JP11707176A patent/JPS5260215A/en active Pending
- 1976-09-29 ES ES451966A patent/ES451966A1/en not_active Expired
- 1976-09-29 CA CA262,319A patent/CA1084823A/en not_active Expired
- 1976-09-30 AT AT0727376A patent/AT370775B/en not_active IP Right Cessation
- 1976-09-30 GB GB4064976A patent/GB1493230A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| SE7610749L (en) | 1977-03-31 |
| BR7606444A (en) | 1977-06-14 |
| JPS5260215A (en) | 1977-05-18 |
| MX143817A (en) | 1981-07-22 |
| SE430901B (en) | 1983-12-19 |
| ATA727376A (en) | 1980-05-15 |
| ES451966A1 (en) | 1978-01-01 |
| NL7610472A (en) | 1977-04-01 |
| DE2643572A1 (en) | 1977-04-07 |
| AT370775B (en) | 1983-05-10 |
| GB1493230A (en) | 1977-11-30 |
| LU75908A1 (en) | 1977-05-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1084823A (en) | Treatment of rolled steel products | |
| NO883781D0 (en) | PROCEDURE FOR TREATMENT OF ROLLING STEEL FOR INCREASING CORROSION RESISTANCE. | |
| GB1149671A (en) | Method of processing ferrous strip | |
| US5672217A (en) | Method for producing machine elements of steel | |
| JP2716127B2 (en) | Method of manufacturing high and low resistance rail | |
| ILCA et al. | Improving the manufacturing technology of structural steels | |
| US2395184A (en) | Continuous production of heattreatable ferrous sections | |
| US2400931A (en) | Continuous production of heattreatable ferrous sections | |
| JPS56122611A (en) | Method and apparatus for manufacture cold rolled sheet product | |
| JPS55110735A (en) | Method and equipment for producing galvanized steel plate for deep drawing use | |
| JPS56150127A (en) | Direct normalizing method | |
| JPS5934214B2 (en) | Method for controlling cooling plate temperature in quenching zone of continuous annealing furnace | |
| JPS57145925A (en) | Production of high strength hot rolled steel plate | |
| CA1191077A (en) | Interrupted quench process | |
| RU2138565C1 (en) | Seamless rolled railway wheel manufacture method | |
| US941134A (en) | Treatment of steel rails. | |
| Semiatin et al. | Induction tempering of steel: Part II. Effect of process variables | |
| Gulyaev et al. | Effect of tempering at subcritical temperatures on the fracture strength of medium carbon structural steel | |
| US2400932A (en) | Continuous production of heattreatable ferrous sections | |
| FR2302340A1 (en) | Brief surface quenching hot rolled steel prod. - leaving a rolling mill, to obtain surface zone of tempered martensite or bainite | |
| RU2006505C1 (en) | Method of manufacture of hot-rolled high-strength sheet steel | |
| RU1786115C (en) | Process for producing heat treated rolled low-carbon and low-alloy steels | |
| SU1280041A1 (en) | Method of heat treatment of seamless rolled wheels | |
| JPS57116727A (en) | Production of high carbon alloy steel wire rod | |
| Petrov et al. | Hardening of Neck Bearing Surfaces of Cold Rolling Mill Rolls |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |