US2708379A - Method of hot rolling stainless steel - Google Patents
Method of hot rolling stainless steel Download PDFInfo
- Publication number
- US2708379A US2708379A US142938A US14293850A US2708379A US 2708379 A US2708379 A US 2708379A US 142938 A US142938 A US 142938A US 14293850 A US14293850 A US 14293850A US 2708379 A US2708379 A US 2708379A
- Authority
- US
- United States
- Prior art keywords
- stainless steel
- hot rolling
- coating
- rolling
- ingot
- 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 - Lifetime
Links
- 229910001220 stainless steel Inorganic materials 0.000 title description 12
- 239000010935 stainless steel Substances 0.000 title description 9
- 238000000034 method Methods 0.000 title description 8
- 238000005098 hot rolling Methods 0.000 title description 5
- 239000011248 coating agent Substances 0.000 description 12
- 238000000576 coating method Methods 0.000 description 12
- 238000005096 rolling process Methods 0.000 description 9
- 239000011230 binding agent Substances 0.000 description 5
- 239000004927 clay Substances 0.000 description 5
- 238000005336 cracking Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 239000004115 Sodium Silicate Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 238000003303 reheating Methods 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000002791 soaking Methods 0.000 description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 3
- 229910052911 sodium silicate Inorganic materials 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000003750 conditioning effect Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical group [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/4981—Utilizing transitory attached element or associated separate material
- Y10T29/49812—Temporary protective coating, impregnation, or cast layer
Definitions
- This invention relates to a method of preparing a stainless steel object for hot working and more particularly to preparing stainless steel ingots, blooms or billets for hot rolling.
- seams are often formed due to checking and cracking during rolling. These checks or cracks may be closed on further rolling, but the metal on the sides of the cracks will not unite.
- the ingot Prior to our invention it was necessary to take certain precautions when rolling such steels.
- the ingot would be heated to a temperature of about 240 i and partially reduced. It was then returned to the soaking pit and reheated for two or three hours to raise the temperature above that at which the ingot would crack or check after which it was again partially reduced.
- the bloom After the second reduction the bloom would be cooled and conditioned by grinding or scarftng. It would then be returned to the soaking pit and reheated for approximately 20 to hours after which it would be rolled to the desired size. In many instances additional reheating and conditioning steps were required. in spite of all these precautions a certain amount of checking and cracking occurred in the finished slab and in many instances the cracking would be so ba that the slab would have to be scrapped and returned to the electric furnace.
- Another object is to provide such a method which will result in eliminating or greatly reducing the cracking and checking which ordinarily occurs when hot reducing stainless steel.
- Still another object is to provide such a method the! will maintain the proper temperatures which will permit the ingot to be rolled to size without reheating and intermediate conditioning.
- the ingot can be rolled through a plurality of passes directly to size without cracking or checking to any extent inasmuch as the coating is adequate to prevent an objectionable drop in temperature.
- the process is preferably carried out as follows:
- the ingot is first heated to a temperature between 300 and 1000 F. (preferably between 500 and 800 F.) and a slurry of a ceramic refractory is applied to the partially heated ingot. in order for the coating to stick properly to the ingot, the surface thereof should be free of loose scale.
- the process is therefore best adapted for those stainless steels which are relatively scaling resistant.
- the refractory is preferably a silicate or mixture of silicates.
- Refractories which have been used with success include "ice a pyrophylite base mixture consisting of between approximately and pyrophylite, between approximately 1% and 5% bentonite, 10% and 25% plastic fire clay, and the balance substantially all sodium silicate; a cold setting cement consisting of burnt clay, raw clay and sodium silicate, and a mixture of crushed silica brick and fire clay.
- a pyrophylite base mixture consisting of between approximately and pyrophylite, between approximately 1% and 5% bentonite, 10% and 25% plastic fire clay, and the balance substantially all sodium silicate
- a cold setting cement consisting of burnt clay, raw clay and sodium silicate, and a mixture of crushed silica brick and fire clay.
- the melting point of the pyrophylite is sufi'icientiy high that the same remains solid at the hot rolling temperature and the sodium silicate and fire clay act as binders which are effective to hold the pyrophylite at both high and low temperatures.
- 2% to 25% of binder may be
- binders in place of the binders mentioned, other well known binders may be used.
- organic binders such as Sulfite Pitch may be used.
- Sufficient liquid is mixed with the refractory to form a slurry of the proper consistency to spray on the ingot at a low pressure since this appears to be the easiest manner of application at present.
- the slurry may be applied at either higher or lower temperatures than those specified, but the specified temperatures are best for practical purposes.
- a coating thickness sufiicient to afford the insulation required is used and a thickness between A; and /2 inch is preferred, but a thickness of /s inch is sufficient in many instances.
- the coating thickness could also be increased to one inch without detrimental effect. but above this thickness there is danger of the coating falling off.
- a thicker coating should be plied adjacent the corners than on the remaining s ce since there is a tendency for the coating to be knocked oi? the corners during the rolling operation.
- the coating is allowed to set and the coated ingot is then charged into the soaking pit and heated to the working temperature which is approximately 2400 F., after which it rolled to size through a plurality of passes.
- the coating is readily removed at room temperature by brushing.
- the method of hot rolling stainless steel through a plurality of passes without reheating which comprises insulating a stainless steel object by covering the same with a relatively thick coating of a ceramic refractory which is solid at the hot working temperature and held together by a suitable hinder, the thickness of the coating being such as to insulate the object sufficiently to hold the temperature of the obiect above approximately 2000 F. during rolling through the several passes and preferably of a thickness of about at least one eighth of an inch, heating the coated object to its hot rolling temperature of about 2400 F. with the refractory thereon, and then rolling the heated object to size by passing it through a plurality of passes.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Metal Rolling (AREA)
Description
United rates atent O METHGD F HGT RGLLTNG STAINLESS STEEL Matti H. Paldrala, littsburgh, and- John L. Scarry, Homestead, Pa., assignors to United States Steel Corpera tion, a corporation of New Hersey No Drawing. Application February 7, 1950, Serial No. 142,938
1 Claim. or. s0 ee This invention relates to a method of preparing a stainless steel object for hot working and more particularly to preparing stainless steel ingots, blooms or billets for hot rolling. In the rolling of stainless steel ingots down to semi-finished stock such as slabs or billets, seams are often formed due to checking and cracking during rolling. These checks or cracks may be closed on further rolling, but the metal on the sides of the cracks will not unite.
These defects are most apparent in stainless steels having poor hot working characteristics, that is, steels which lose ductility when they cool below tern eratures of approximately 1950 and 2000" F. and therefore crack and check at this temperature. Austenitic stainless steels, such as those containing 25% chromium and nickel fall in this category.
Prior to our invention it was necessary to take certain precautions when rolling such steels. The ingot would be heated to a temperature of about 240 i and partially reduced. it was then returned to the soaking pit and reheated for two or three hours to raise the temperature above that at which the ingot would crack or check after which it was again partially reduced. After the second reduction the bloom would be cooled and conditioned by grinding or scarftng. It would then be returned to the soaking pit and reheated for approximately 20 to hours after which it would be rolled to the desired size. In many instances additional reheating and conditioning steps were required. in spite of all these precautions a certain amount of checking and cracking occurred in the finished slab and in many instances the cracking would be so ba that the slab would have to be scrapped and returned to the electric furnace.
It is therefore an object of our invention to provide a method of preparing stainless steel ingots for rolling which will cause an increase in the average yield from the ingots.
Another object is to provide such a method which will result in eliminating or greatly reducing the cracking and checking which ordinarily occurs when hot reducing stainless steel.
Still another object is to provide such a method the! will maintain the proper temperatures which will permit the ingot to be rolled to size without reheating and intermediate conditioning.
These and other objects will be more apparent after referring to the following description.
We have found that by putting a coating of ceramic refractory on the ingot prior to rolling, the ingot can be rolled through a plurality of passes directly to size without cracking or checking to any extent inasmuch as the coating is suficient to prevent an objectionable drop in temperature. The process is preferably carried out as follows:
The ingot is first heated to a temperature between 300 and 1000 F. (preferably between 500 and 800 F.) and a slurry of a ceramic refractory is applied to the partially heated ingot. in order for the coating to stick properly to the ingot, the surface thereof should be free of loose scale. The process is therefore best adapted for those stainless steels which are relatively scaling resistant. The refractory is preferably a silicate or mixture of silicates. Refractories which have been used with success include "ice a pyrophylite base mixture consisting of between approximately and pyrophylite, between approximately 1% and 5% bentonite, 10% and 25% plastic fire clay, and the balance substantially all sodium silicate; a cold setting cement consisting of burnt clay, raw clay and sodium silicate, and a mixture of crushed silica brick and fire clay. hi the above mixtures the melting point of the pyrophylite is sufi'icientiy high that the same remains solid at the hot rolling temperature and the sodium silicate and fire clay act as binders which are effective to hold the pyrophylite at both high and low temperatures. Ordinarily from 2% to 25% of binder may be used, but it is preferred to use not more than 15%. in place of the binders mentioned, other well known binders may be used. For example, organic binders, such as Sulfite Pitch may be used. Sufficient liquid is mixed with the refractory to form a slurry of the proper consistency to spray on the ingot at a low pressure since this appears to be the easiest manner of application at present. The slurry may be applied at either higher or lower temperatures than those specified, but the specified temperatures are best for practical purposes. A coating thickness sufiicient to afford the insulation required is used and a thickness between A; and /2 inch is preferred, but a thickness of /s inch is sufficient in many instances. The coating thickness could also be increased to one inch without detrimental effect. but above this thickness there is danger of the coating falling off. A thicker coating should be plied adjacent the corners than on the remaining s ce since there is a tendency for the coating to be knocked oi? the corners during the rolling operation. The coating is allowed to set and the coated ingot is then charged into the soaking pit and heated to the working temperature which is approximately 2400 F., after which it rolled to size through a plurality of passes. The coating is readily removed at room temperature by brushing.
While one embodiment of our invention has been described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claim.
We claim:
The method of hot rolling stainless steel through a plurality of passes without reheating which comprises insulating a stainless steel object by covering the same with a relatively thick coating of a ceramic refractory which is solid at the hot working temperature and held together by a suitable hinder, the thickness of the coating being such as to insulate the object sufficiently to hold the temperature of the obiect above approximately 2000 F. during rolling through the several passes and preferably of a thickness of about at least one eighth of an inch, heating the coated object to its hot rolling temperature of about 2400 F. with the refractory thereon, and then rolling the heated object to size by passing it through a plurality of passes.
References Cited in the file of this patent UNITED STATES PATENTS 322,290 Hines July 14, 1885 1,080,059 Hatfield Dec. 2, 1913 1,085,768 Thompson Feb. 3, 1914 1,432,523 Bickley Oct. 17, 1922 1,505,215 lvieloche Aug. 19, 1924 1,879,701 Marino Sept. 27, 1932 1,922,005 Stocking Aug. 8, 1933 2,121,606 McCulloch June 21, 1938 2,142,869 Fraser Ian. 3, 1939 2,430,083 Sherman Nov. 4, 1947 FOREIGN PATENTS 300,633 Great Britain Nov. 28, 1929
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US142938A US2708379A (en) | 1950-02-07 | 1950-02-07 | Method of hot rolling stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US142938A US2708379A (en) | 1950-02-07 | 1950-02-07 | Method of hot rolling stainless steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2708379A true US2708379A (en) | 1955-05-17 |
Family
ID=22501882
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US142938A Expired - Lifetime US2708379A (en) | 1950-02-07 | 1950-02-07 | Method of hot rolling stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2708379A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2869227A (en) * | 1955-07-01 | 1959-01-20 | Armour Res Found | Process of coating and hot working of metals |
| US2968092A (en) * | 1956-02-13 | 1961-01-17 | Yawata Iron & Steel Co | Process of working steel for preventing surface defects thereof |
| US3192752A (en) * | 1963-06-27 | 1965-07-06 | Aluminum Co Of America | Cold rolling aluminum and product |
| US3230750A (en) * | 1962-09-14 | 1966-01-25 | Rolls Royce | Forming and heat treatment of sheetmetal articles with organophilic cation-modified clay |
| US3287954A (en) * | 1962-08-30 | 1966-11-29 | Inland Steel Co | Method for heating steel billets |
| US3296846A (en) * | 1964-06-05 | 1967-01-10 | Crucible Steel Co America | Method of rolling steel |
| DE1270521B (en) * | 1960-09-23 | 1968-06-20 | Thyssen Roehrenwerke Ag | Thermal insulation in extrusion presses between die and press block |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US322290A (en) * | 1885-07-14 | Process of making enameled goods | ||
| US1080059A (en) * | 1912-12-10 | 1913-12-02 | John Adams Hatfield | Process for producing clean or deoxidized metal surfaces. |
| US1085768A (en) * | 1912-03-08 | 1914-02-03 | Int Nickel Co | Process of preventing oxidation of metals during annealing. |
| US1432523A (en) * | 1920-12-28 | 1922-10-17 | Bickley Allen | Coating composition |
| US1505215A (en) * | 1924-08-19 | Daniel h | ||
| GB300633A (en) * | 1927-11-17 | 1929-11-28 | Pierre Francois Marie Aubert | Improvements in hardening iron and steel articles by nitrogenization |
| US1879701A (en) * | 1931-11-20 | 1932-09-27 | Anthony J Marino | Protective coating and method of applying same to nickel, nickel alloys, and chromium-iron alloys |
| US1922005A (en) * | 1929-04-02 | 1933-08-08 | Williams Brothers Mfg Company | Method of plating |
| US2121606A (en) * | 1936-07-31 | 1938-06-21 | Westinghouse Electric & Mfg Co | Coating for ferrous alloys |
| US2142869A (en) * | 1936-10-01 | 1939-01-03 | Int Nickel Co | Treatment of nickel-chromium alloys |
| US2430083A (en) * | 1944-01-27 | 1947-11-04 | Smith Corp A O | Method of forging and lubricant therefor |
-
1950
- 1950-02-07 US US142938A patent/US2708379A/en not_active Expired - Lifetime
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US322290A (en) * | 1885-07-14 | Process of making enameled goods | ||
| US1505215A (en) * | 1924-08-19 | Daniel h | ||
| US1085768A (en) * | 1912-03-08 | 1914-02-03 | Int Nickel Co | Process of preventing oxidation of metals during annealing. |
| US1080059A (en) * | 1912-12-10 | 1913-12-02 | John Adams Hatfield | Process for producing clean or deoxidized metal surfaces. |
| US1432523A (en) * | 1920-12-28 | 1922-10-17 | Bickley Allen | Coating composition |
| GB300633A (en) * | 1927-11-17 | 1929-11-28 | Pierre Francois Marie Aubert | Improvements in hardening iron and steel articles by nitrogenization |
| US1922005A (en) * | 1929-04-02 | 1933-08-08 | Williams Brothers Mfg Company | Method of plating |
| US1879701A (en) * | 1931-11-20 | 1932-09-27 | Anthony J Marino | Protective coating and method of applying same to nickel, nickel alloys, and chromium-iron alloys |
| US2121606A (en) * | 1936-07-31 | 1938-06-21 | Westinghouse Electric & Mfg Co | Coating for ferrous alloys |
| US2142869A (en) * | 1936-10-01 | 1939-01-03 | Int Nickel Co | Treatment of nickel-chromium alloys |
| US2430083A (en) * | 1944-01-27 | 1947-11-04 | Smith Corp A O | Method of forging and lubricant therefor |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2869227A (en) * | 1955-07-01 | 1959-01-20 | Armour Res Found | Process of coating and hot working of metals |
| US2968092A (en) * | 1956-02-13 | 1961-01-17 | Yawata Iron & Steel Co | Process of working steel for preventing surface defects thereof |
| DE1270521B (en) * | 1960-09-23 | 1968-06-20 | Thyssen Roehrenwerke Ag | Thermal insulation in extrusion presses between die and press block |
| US3287954A (en) * | 1962-08-30 | 1966-11-29 | Inland Steel Co | Method for heating steel billets |
| US3230750A (en) * | 1962-09-14 | 1966-01-25 | Rolls Royce | Forming and heat treatment of sheetmetal articles with organophilic cation-modified clay |
| US3192752A (en) * | 1963-06-27 | 1965-07-06 | Aluminum Co Of America | Cold rolling aluminum and product |
| US3296846A (en) * | 1964-06-05 | 1967-01-10 | Crucible Steel Co America | Method of rolling steel |
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