Material and process of manufacture of steel components for screw gun clutches
A process for manufacturing highly wear and fatigue resistant steel components for power tools includes melting and mixing together a readily available base steel and alloying elements. The molten steel is cast into near-net-shape in an investment casting process. This method is cost competitive with forming the same component from steel with fewer alloying elements. In particular, clutch plates for a drill/driver or screw gun can be formed in this manner from a steel containing relatively large amounts of nickel and chromium, such as SAE 9310 steel, or from a steel containing a relatively large total amount of molybdenum and tungsten, such as AISI M2 steel.
1 . A method of making a highly wear and fatigue resistant component comprising:
providing a quantity of base steel;
providing a quantity of alloying elements to be added to the base steel to form a desired alloyed grade of steel;
combining and melting the quantity of base steel and the quantity of alloying elements to produce a molten alloyed steel; and
casting the molten alloyed steel in a near-net-shape investment casting process to form Me a component whereby no further machining is necessary to form the component.
2 . (canceled)
3 . The method of claim 1 wherein the alloying elements include:
about 1%-3.5% nickel by weight; and
about 0.4%-1.4% chromium by weight.
4 . The method of claim 1 wherein the alloying elements include:
at least about 3% nickel by weight; and
at least about 1% chromium by weight.
5 . The method of claim 1 further comprising:
case hardening the component after it is cast.
6 . The method of claim 5 further comprising
subjecting the component to a cryogenic treatment after case hardening.
7 . The method of claim 6 wherein the cryogenic treatment includes cooling the component in a medium with a temperature less than about −180 degrees Fahrenheit.
8 . (canceled)
9 . The method of claim 1 wherein the alloying elements include:
a total amount of molybdenum and tungsten of about 5%-11% by weight.
10 . The method of claim 1 wherein the alloying elements include:
at least a total amount of molybdenum and tungsten of 9% by weight.
11 . The method of claim 10 wherein the alloying elements include:
at least approximately 0.5% vanadium by weight; and
at least approximately 3% chromium by weight.
12 . (canceled)
13 - 20 . (canceled)
21 . The method of claim 1 further comprising pre-radiusing an edge of the component.
22 . The method of claim 21 further comprising case hardening the component, wherein case hardening occurs after pre-radiusing the edge.
23 . The method of claim 1 wherein the base steel comprises SAE 1010 steel.
24 . The method of claim 5 wherein case hardening comprises carburizing the component.
25 . The method of claim 5 wherein case hardening comprises nitriding the component.
26 . The method of claim 5 further comprising heat treating the component after case hardening.
27 . The method of claim 5 wherein case hardening comprises hardening the component to about 62-65 Rockwell C.
28 . A method of making a component for a power tool comprising:
providing a quantity of base steel;
melting the quantity of base steel;
providing a quantity of alloying elements, wherein the alloying elements comprise at least one element selected from the group consisting of nickel, chromium, molybdenum, tungsten, and vanadium;
combining the quantity of alloying elements with the base steel to produce a molten alloyed steel; and
casting the molten alloyed steel in a near-net-shape investment casting process to form a clutch.
29 . The method of claim 28 wherein the clutch comprises a lug having an edge.
30 . The method of claim 29 further comprising pre-radiusing the edge of the lug.
31 . The method of claim 28 , further comprising case hardening the clutch.
32 . The method of claim 31 further comprising heat treating the clutch after case hardening.
33 . The method of claim 28 wherein the alloying elements comprise about 1%-3.5% nickel by weight and about 0.4%-1.4% chromium by weight.
34 . The method of claim 28 wherein the alloying elements include a total amount of molybdenum and tungsten of about 5%-11% by weight.
35 . The method of claim 28 wherein the alloying elements include at least approximately 0.5% vanadium by weight and at least approximately 3% chromium by weight.