Method and tool product of differential heat treatment process

Patent metadata

Field	Value
Publication number	US-10434611-B2
Application number	US-201815913469-A
Country	US
Kind code	B2
Filing date	Mar 6, 2018
Priority date	Oct 8, 2008
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

A tool having a relatively ductile working end for engaging workpieces and a relatively hard non-working portion for driving the tool is disclosed, and a process for making same. The tool is formed with the material in a first state, such as by cold-working, and then only the non-working portion is heat treated to a second state. The working end is thus maintained in the ductile state while the non-working portion is hardened, thus imparting different materials performance characteristics to working end and non-working portion.

First claim

What is claimed is:

1. A method for heat treating a tool, the method comprising the steps of:
forming the tool with a stem portion having a first end adapted to couple to a driver and receive an amount of torque from the driver, a shoulder portion extending from the stem portion opposite the first end, a working portion extending from the shoulder portion opposite the stem portion and including a recess adapted to receive a device adapted to engage a work piece, and a zero-treatment region extending from the working portion to an end of the tool and forms only an opening of the recess;
heat treating the stem portion to a first depth to form substantially tempered martensite steel to the first depth, wherein the first depth is measured in a radial direction from an external surface of the stem portion towards a center of the stem portion, and the first depth forms at least 75% of an overall diametric size of the stem portion; and
providing no direct heat treatment to the shoulder and working portions and the zero-treatment region, wherein the shoulder and working portions are at least partially comprised of a material including tempered steel created by residual heat from the heat treating, and are substantially free of tempered martensite steel after the heat treating, and wherein the zero-treatment region is comprised of a material free of tempered martensite steel and tempered steel.

2. The method of claim 1 , wherein the step of heat treating includes placing the stem portion in a heating device.

3. The method of claim 1 , wherein the step of heat treating includes placing the stem portion in an induction coil.

4. The method of claim 1 , wherein the step of forming the tool includes forming the tool of a steel alloy, and wherein the step of heat treating includes:
heating the stem portion to a first temperature;
quenching the stem portion;
heating the stem portion to a second temperature below the first temperature; and
cooling the stem portion.

5. The method of clam 4 , wherein the step of cooling includes quenching.

6. The method of claim 1 , wherein the step of forming the tool includes forming the tool from stock material having a predetermined materials state.

7. The method of claim 1 , wherein the step of forming the tool includes forming the zero-treatment region with a hardness of about 20 HRc.

8. The method of claim 1 , wherein the step of forming the tool includes the step of forming a socket driver extension.

9. A method of forming a tool, comprising:
forming the tool from a base material, the tool having a working portion adapted to engage a work piece and a non-working portion;
heat treating at least a part of the non-working portion to a first depth, wherein the first depth is measured in a radial direction from an external surface towards a center of the non-working portion, and the first depth forms at least 75% of an overall diametric size of the non-working portion;
providing no direct heat treatment to an end of the working portion, wherein a portion of the tool between the working and non-working portions is subject to residual heat from the heat treating.

10. The method of claim 9 , wherein the step of heat treating includes heat treating at least the part of the non-working portion to the depth to form substantially tempered martensite steel to the first depth.

11. The method of claim 9 , wherein the step of providing no direct heat treatment includes subjecting the portion of the tool between the working and non-working portions to residual heat from the heat treating, wherein the portion of the tool between the working and non-working portions is at least partially comprised of a material including tempered steel and substantially free of tempered martensite steel after the heat treating, and wherein the end of the working portion is comprised of a material free of tempered martensite steel and tempered steel.

12. The method of claim 9 , wherein the step of forming the tool includes forming the tool of a steel alloy, and wherein the step of heat treating includes:
heating the non-working portion to a first temperature;
quenching the non-working portion;
heating the non-working portion to a second temperature below the first temperature; and
cooling the non-working portion.

13. The method of clam 12 , wherein the step of cooling includes quenching.

14. The method of claim 9 , wherein the step of forming the tool includes forming the tool from stock material having a predetermined materials state.

Assignees

• Snap On Tools Corp

Inventors

• Eggert Daniel M

Classifications

• B25B15/002

  characterised by material used or surface finishing · CPC title

• B25B13/00

  Spanners; Wrenches (hand-driven gear-operated B25B17/00; impact wrenches B25B19/00; portable power-driven B25B21/00 {; spanners or wrenches pecially adapted for osteosynthesis A61B17/8875}; machines for fitting together or separating metal parts B23P19/00 {; for mounting or dismounting wheels B60B29/003}) · CPC title

• C21D2211/008

  Martensite · CPC title

• C21D1/18

  Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62) · CPC title

• Y10T29/49

  Method of mechanical manufacture · CPC title