EP0225414A1 - A new steel - Google Patents
A new steel Download PDFInfo
- Publication number
- EP0225414A1 EP0225414A1 EP85308967A EP85308967A EP0225414A1 EP 0225414 A1 EP0225414 A1 EP 0225414A1 EP 85308967 A EP85308967 A EP 85308967A EP 85308967 A EP85308967 A EP 85308967A EP 0225414 A1 EP0225414 A1 EP 0225414A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- steel
- temperature
- product
- melt
- percentages
- 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.)
- Withdrawn
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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
-
- 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
Definitions
- This invention relates to a new steel.
- Wear is one of most commonly encountered problems in equipment used during mining operations. There is an increasing trend towards mechanical systems in mining. Their success to a large extent will depend on overcoming the problem of severe abrasive wear in South Africa associated with the mining and handling of extremely hard abrasive quartzitic ore. To warrant the expense of manufacturing such systems their components should have as extended a wear life as possible.
- a steel according to the invention comprises, apart from iron and incidental impurities, 0,22 to 0,27% carbon 7,0 to 8,5% chromium and 2,8 to 3,2% nickel, all percentages being by mass. A nominal 8% of Cr should be aimed at.
- this steel after 7 passes shows a fairly high Vickers hardness, but a relatively low toughness on the Charpy scale.
- the steel should be heated to a temperature of the order of 1100°C and oil quenched. Tempering at a temperature of between 200 and 250°C improves the toughness still further. A further heat treatment does not improve the toughness, but at some sacrifice of toughness a slight increase in hardness may be obtained.
- a steel was made which in addition to iron contained the following elements in the given percentages by mass: C 0,24, Cr 7,08, Ni 3,2, S0,007, P 0,012, Si 0,027, Mn 0,02 and Mo 0,01.
- a 5 kg ingot 54mm square was rolled to a 12 mm flat bar in about seven passes. At the start of each pass the temperature was 1100°C. The finishing temperature was not measured.
- the microstructure of the heat treated product was a fine-grained low carbon martensite with retained austenite.
- the components were characterised by having high strength and good ductility.
- the steel also showed a high hardness with good toughness. Usually hardness and toughness are mutually exclusive.
- the steel was found to be readily machinable and weldable so that special fabrication practices are not called for. Due to its hardness and toughness the steel is only 40% as machinable an En9 steel.
Abstract
Description
- This invention relates to a new steel.
- Wear is one of most commonly encountered problems in equipment used during mining operations. There is an increasing trend towards mechanical systems in mining. Their success to a large extent will depend on overcoming the problem of severe abrasive wear in South Africa associated with the mining and handling of extremely hard abrasive quartzitic ore. To warrant the expense of manufacturing such systems their components should have as extended a wear life as possible.
- In a mining environment wear takes places due to abrasion and also due to corrosion by mine waters. Thus conventional stainless steel lasts much longer in a mining environment, in the absence of extreme abrasion, than mild steel due to the corrosion resistance of stainless steel.
- It is an object of the invention to provide a new steel which is both corrosion and abrasion resistant to a greater extent then commercially available steels.
- A steel according to the invention comprises, apart from iron and incidental impurities, 0,22 to 0,27% carbon 7,0 to 8,5% chromium and 2,8 to 3,2% nickel, all percentages being by mass. A nominal 8% of Cr should be aimed at.
- Further according to the invention, if the following incidental impurities are present they should not exceed the percentages stated below:
- Sulphur 0,008, phosphorous 0,02, copper 0,2, tin 0,03, titanium 0,001, manganese 0,5, molybdenum 0,06 and aluminium 0,05.
- In the as rolled condition this steel after 7 passes shows a fairly high Vickers hardness, but a relatively low toughness on the Charpy scale. To improve the latter the steel should be heated to a temperature of the order of 1100°C and oil quenched. Tempering at a temperature of between 200 and 250°C improves the toughness still further. A further heat treatment does not improve the toughness, but at some sacrifice of toughness a slight increase in hardness may be obtained.
- In an example of the invention a steel was made which in addition to iron contained the following elements in the given percentages by mass: C 0,24, Cr 7,08, Ni 3,2, S0,007, P 0,012, Si 0,027, Mn 0,02 and Mo 0,01.
- A 5 kg ingot 54mm square was rolled to a 12 mm flat bar in about seven passes. At the start of each pass the temperature was 1100°C. The finishing temperature was not measured.
-
- The microstructure of the heat treated product was a fine-grained low carbon martensite with retained austenite.
- Four tons of the above described steel were made by a local steelmaker and made into components for testing. The components were heat treated as in sample A3. Parts were welded together before heat treatment.
- The components were characterised by having high strength and good ductility. The steel also showed a high hardness with good toughness. Usually hardness and toughness are mutually exclusive.
- As indicated above, the limits for many impurities are fairly high so that standard steel making practices and equipment can be used.
- The steel was found to be readily machinable and weldable so that special fabrication practices are not called for. Due to its hardness and toughness the steel is only 40% as machinable an En9 steel.
- In situations where the product was exposed to the synergistic effects of corrosion and abrasion, the steel performed exceptionally well, better than commercial abrasion resistant steels. Commercial stainless steel are more corrosion resistant, but have higher coefficients of friction which makes them unsuitable for applications involving sliding abrasion, such as shaker conveyers.
Claims (6)
sulphur 0,008, phosphorous 0,02, copper 0,2 tin 0,03, titanium 0,001, manganese 0,5, molybdenum 0,06 and aluminium 0,05.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ZA836821 | 1983-09-14 | ||
ZA847054A ZA847054B (en) | 1983-09-14 | 1984-09-07 | A new steel |
GB08429776A GB2167437B (en) | 1983-09-14 | 1984-11-26 | Method of making novel alloy steel |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0225414A1 true EP0225414A1 (en) | 1987-06-16 |
Family
ID=39615654
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85308967A Withdrawn EP0225414A1 (en) | 1983-09-14 | 1985-12-10 | A new steel |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0225414A1 (en) |
GB (1) | GB2167437B (en) |
ZA (1) | ZA847054B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109055849A (en) * | 2018-07-12 | 2018-12-21 | 潍坊科技学院 | Steel/quartz sand preparation high-wearing feature brake block and preparation method thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1560099A (en) * | 1925-04-27 | 1925-11-03 | George R Rich | Heat-resisting alloy steel and articles made therefrom |
CH415068A (en) * | 1959-11-02 | 1966-06-15 | Atomic Energy Commission | Steel alloy |
CH415067A (en) * | 1959-06-24 | 1966-06-15 | Bofors Ab | Process for the production of a weldable, hardenable and corrosion-resistant steel |
-
1984
- 1984-09-07 ZA ZA847054A patent/ZA847054B/en unknown
- 1984-11-26 GB GB08429776A patent/GB2167437B/en not_active Expired
-
1985
- 1985-12-10 EP EP85308967A patent/EP0225414A1/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1560099A (en) * | 1925-04-27 | 1925-11-03 | George R Rich | Heat-resisting alloy steel and articles made therefrom |
CH415067A (en) * | 1959-06-24 | 1966-06-15 | Bofors Ab | Process for the production of a weldable, hardenable and corrosion-resistant steel |
CH415068A (en) * | 1959-11-02 | 1966-06-15 | Atomic Energy Commission | Steel alloy |
Also Published As
Publication number | Publication date |
---|---|
GB2167437B (en) | 1988-07-06 |
ZA847054B (en) | 1986-04-30 |
GB8429776D0 (en) | 1985-01-03 |
GB2167437A (en) | 1986-05-29 |
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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 BE DE FR IT NL |
|
17P | Request for examination filed |
Effective date: 19871022 |
|
17Q | First examination report despatched |
Effective date: 19890303 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Withdrawal date: 19891003 |
|
R18W | Application withdrawn (corrected) |
Effective date: 19891003 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: HEATHCOCK, CHRISTOPHER JOHN Inventor name: GARRETT, GEOFFREY GRAHAM Inventor name: PROTHEROE, BRIAN EDWARD |