Low-sulfur, lead-free free machining steel alloy
AssigneeFrema, Inc.
InventorMichael O. Holowaty
Life of this patent
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Abstract
Composition and continuous casting method for producing a low-sulphur, free-machining steel, substantially free of lead and including in weight percent about 0.05-0.40 copper, 0.005-0.040 tellurium, 0.002-0.15 bismuth, 0.002-0.05 tin, up to 0.55 carbon, and less than 0.25 sulphur, traces (up to about 0.005 weight percent) of barium, and the balance being iron. The elements bismuth, tellurium and tin are added as a molten alloy to the molten steel and uniformly distributed therethrough. The elements copper and barium can be added separately into the steel stream ahead of the molten addition inflow. The mass is then cooled to provide a solid metal casting substantially free of blemishes and relatively free of surface checking and tearing. The casting is characterized by enhanced machining properties.
Claims13
A low-sulfur, free-machining steel substantially free of lead and consisting essentially of, in percent by weight
- Sulfur :
- 0.02-0.06
- Copper :
- 0.05-0.40
- Bismuth :
- 0.002-0.15
- Nickel :
- less than about 0.08
- Chromium :
- less than about 0.08
- Tin :
- 0.002-0.05
- and the balance consisting essentially of iron, and in which the combined concentration of copper, nickel, chromium and tin exceeds the concentration of bismuth.
Dependencies are inferred from the claim text.