STELLITE
Posted: 22 Apr 2012, 09:58
STELLITE
I had occasion to have a furtle for some information about Stellite today and was quite surprised when I could find no information in my favourite source; Osborne’s ‘Encyclopaedia of the Iron and Steel Industry’. No mention. So I turned to some more esoteric sources, the first was an old American book, ‘A Fortune in Formulas for the farm, home and workshop’ a strange mixture but very informative. Here’s what that had to say: “In the United States we have a stainless alloy termed Stellite, one consisting of 75% Cobalt and 25% Chromium invented by Elwood Haynes of Kokomo, Indiana. It is used for lathe tools, surgical knives and cutlery and is stainless.”
Machinery’s Handbook (15th Edition, 1956) has this to say: Haynes Stellite is an alloy of cobalt, chromium and Tungsten and is non-ferrous as it has no iron in its composition. The hardness of this alloy is not affected by heat up to 1,500F and is actually tougher at red heat than when cold. This important property explains its wide application as a cutting tool material. It works best at high speed with a comparatively light feed. The cutting material known as ‘J Metal’ is an improved grade of Haynes Stellite. This results in either higher cutting speed or longer production runs between tool grinding. It is used on all kinds of difficult materials except for Chilled Iron and Manganese steel. Hayne’s Stellite 2400 is an even better grade and gives higher performance.
Both these sources are a bit old-fashioned nowadays and I can’t remember the last time I saw Stellite used for cutting. I have some of the material and one of these days I’ll find a use for it but modern tool steel alloys and carbide tipped tools have largely superseded Stellite.
Wykepedia of course came up with a reference.
Stellite alloy is a range of cobalt-chromium alloys designed for wear resistance. It may also contain tungsten and a small but important amount of carbon. It is a trademark name of the Deloro Stellite Company and was invented by Elwood Haynes in the early 1900's as a substitute for flatware that stained (or that had to be constantly cleaned).
Properties
Stellite® alloy is a completely non-magnetic and non-corrosive cobalt alloy. There are a number of Stellite® alloys, with various compositions optimised for different uses. Information is available from the manufacturer, Deloro Stellite®, outlining the composition of a number of Stellite® alloys and their intended applications. The alloy currently most suited for cutting tools, for example, is Stellite® 100, due to the fact that this alloy is quite hard, maintains a good cutting edge even at high temperature, and resists hardening and annealing due to heat. Other alloys are formulated to maximize combinations of wear resistance, corrosion resistance, or ability to withstand extreme temperatures.
Stellite® alloys display astounding hardness and toughness, and are also usually very resistant to corrosion. Stellite® alloys are so hard that they are very difficult to machine, and anything made from them is, as a result, very expensive. Typically a Stellite® part will be very precisely cast so that only minimal machining will be necessary. Machining of Stellite® is more often done by grinding, rather than by cutting. Stellite® alloys also tend to have extremely high melting points due to the cobalt and chromium content.
Applications
Typical applications include saw teeth, hard-facing (wear-resistant welding) and also for acid-resistant machine parts. Stellite® was a major improvement in the production of poppet valves and valve seats in internal combustion engines; by reducing wear in them, the competing slide-valve design was driven from the market. The first third of M-60 machine gun barrels (starting from the chamber) are lined with Stellite®. Modern jet engine turbine blades are usually made of Stellite® alloys, due to their very high melting points and tremendous strength at very high temperatures. In the early 1980s experiments were done in the United Kingdom to make artificial hip joints and other bone replacements out of precision-cast Stellite® alloys.
Stellite® has also been used in the manufacture of turning tools for Lathes. With the introduction and improvements in tipped tools it is not used as often any more, but it was found to have superior cutting properties compared to the early carbon steel tools and even some High Speed Steel tools, especially against difficult materials as stainless steel. Care was needed in grinding the blanks and these were marked at one end to show the correct orientation, without which the cutting edge could chip prematurely.
Varieties
Talonite is a Stellite® alloy which has been hot-rolled and hardened in a particular way, to provide a combination of hardness, wear resistance and machineability. Not all Stellite® alloys respond to this process.
SCG/07 January 2007
I had occasion to have a furtle for some information about Stellite today and was quite surprised when I could find no information in my favourite source; Osborne’s ‘Encyclopaedia of the Iron and Steel Industry’. No mention. So I turned to some more esoteric sources, the first was an old American book, ‘A Fortune in Formulas for the farm, home and workshop’ a strange mixture but very informative. Here’s what that had to say: “In the United States we have a stainless alloy termed Stellite, one consisting of 75% Cobalt and 25% Chromium invented by Elwood Haynes of Kokomo, Indiana. It is used for lathe tools, surgical knives and cutlery and is stainless.”
Machinery’s Handbook (15th Edition, 1956) has this to say: Haynes Stellite is an alloy of cobalt, chromium and Tungsten and is non-ferrous as it has no iron in its composition. The hardness of this alloy is not affected by heat up to 1,500F and is actually tougher at red heat than when cold. This important property explains its wide application as a cutting tool material. It works best at high speed with a comparatively light feed. The cutting material known as ‘J Metal’ is an improved grade of Haynes Stellite. This results in either higher cutting speed or longer production runs between tool grinding. It is used on all kinds of difficult materials except for Chilled Iron and Manganese steel. Hayne’s Stellite 2400 is an even better grade and gives higher performance.
Both these sources are a bit old-fashioned nowadays and I can’t remember the last time I saw Stellite used for cutting. I have some of the material and one of these days I’ll find a use for it but modern tool steel alloys and carbide tipped tools have largely superseded Stellite.
Wykepedia of course came up with a reference.
Stellite alloy is a range of cobalt-chromium alloys designed for wear resistance. It may also contain tungsten and a small but important amount of carbon. It is a trademark name of the Deloro Stellite Company and was invented by Elwood Haynes in the early 1900's as a substitute for flatware that stained (or that had to be constantly cleaned).
Properties
Stellite® alloy is a completely non-magnetic and non-corrosive cobalt alloy. There are a number of Stellite® alloys, with various compositions optimised for different uses. Information is available from the manufacturer, Deloro Stellite®, outlining the composition of a number of Stellite® alloys and their intended applications. The alloy currently most suited for cutting tools, for example, is Stellite® 100, due to the fact that this alloy is quite hard, maintains a good cutting edge even at high temperature, and resists hardening and annealing due to heat. Other alloys are formulated to maximize combinations of wear resistance, corrosion resistance, or ability to withstand extreme temperatures.
Stellite® alloys display astounding hardness and toughness, and are also usually very resistant to corrosion. Stellite® alloys are so hard that they are very difficult to machine, and anything made from them is, as a result, very expensive. Typically a Stellite® part will be very precisely cast so that only minimal machining will be necessary. Machining of Stellite® is more often done by grinding, rather than by cutting. Stellite® alloys also tend to have extremely high melting points due to the cobalt and chromium content.
Applications
Typical applications include saw teeth, hard-facing (wear-resistant welding) and also for acid-resistant machine parts. Stellite® was a major improvement in the production of poppet valves and valve seats in internal combustion engines; by reducing wear in them, the competing slide-valve design was driven from the market. The first third of M-60 machine gun barrels (starting from the chamber) are lined with Stellite®. Modern jet engine turbine blades are usually made of Stellite® alloys, due to their very high melting points and tremendous strength at very high temperatures. In the early 1980s experiments were done in the United Kingdom to make artificial hip joints and other bone replacements out of precision-cast Stellite® alloys.
Stellite® has also been used in the manufacture of turning tools for Lathes. With the introduction and improvements in tipped tools it is not used as often any more, but it was found to have superior cutting properties compared to the early carbon steel tools and even some High Speed Steel tools, especially against difficult materials as stainless steel. Care was needed in grinding the blanks and these were marked at one end to show the correct orientation, without which the cutting edge could chip prematurely.
Varieties
Talonite is a Stellite® alloy which has been hot-rolled and hardened in a particular way, to provide a combination of hardness, wear resistance and machineability. Not all Stellite® alloys respond to this process.
SCG/07 January 2007
