WELD-PENETRATION CONTROL

• US 3,567,899 A
• Filed: 03/30/1966
• Issued: 03/02/1971
• Est. Priority Date: 03/30/1966
• Status: Expired due to Term

• Current Assignee: Martin E O'Dor, William F. Iceland
• Original Assignee: Martin E O'Dor, William F. Iceland
• Inventors: Iceland, William F., O'dor, Martin E.
• Application Number:
  US04/538,650
• Time in Patent Office: 1,798 Days
• US Class Current: 219/124.34
• CPC Class Codes: B23K 9/0956 using sensing means, e.g. optical

Abstract

In order to provide improved weld-penetration control, the temperature produced by the welding operation is monitored; and resultant control-signals are used to produce improved welding.

Claims

1. A method for fusion welding a workpiece to control weld penetratiOn, comprising the steps of:

supplying power to and heating an area on one side of said workpiece in which a fusion weld is to be formed forming a weld-puddle;

causing the heated area to move relative to the workpiece, so that the point of formation of said weld-puddle moves relative to the workpiece;

sensing the heat output emanating from the other side of the workpiece at the point thereon at which the moving weld-puddle is being formed by sensing a predetermined band of wavelengths in the infrared region and cutting off visual wavelengths; and

controlling the power input to the moving weld-puddle in accordance with the heat output from the opposite side of said weld-puddle within the specified band sensed by the sensor to maintain consistent penetration of the weld at a predetermined value.

2. The method of claim 1 wherein said heating step comprises establishing an arc between a non combustible electrode and said workpiece, and said power-controlling step comprises controlling the current in said arc.

3. The method of claim 1 wherein said heating step comprises establishing an arc between a combustible electrode and said workpiece, and said power-controlling step comprises controlling the arc-length.

4. The method of claim 1 wherein said heating step comprises application of heat by a welding torch, and said power-controlling step comprises controlling the flow of gas to said torch.

5. A method for controlling on a workpiece a welding operation that continuously produces a weld-puddle on one side of the workpiece which puddle moves relative to the workpiece, in order to attain improved penetration and prevent blow-through, comprising the steps of:

monitoring the temperature of said workpiece at a point disposed on the opposite side thereof from said moving weld-puddle;

producing a monitoring signal when said temperature changes from a given value; and

causing said monitoring signal to control the power input to said moving weld-puddle to minimize the danger of blow-through.

6. The combination of claim 5 wherein said monitoring signal is amplified to produce a control signal indicative of the change in temperature of said moving weld-puddle;

and causing said control signal to control the power applied to said weld-puddle.

7. The combination of claim 5 wherein said temperature monitoring comprises the measurement of infrared radiation from a small area of said moving weld-puddle.

8. The combination of claim 7 wherein said power input depends upon the arc-current, and said control signal controls said arc-current.

9. The combination of claim 7 wherein said power input depends upon the arc-length, and said control signal controls said arc-length.

10. The combination of claim 7 wherein said control signal controls the flow of gas to a welding torch.