HEAT INPUT TO WELDING

HOW TO CALCULATE HEAT INPUT TO THE WELDING

HEAT INPUT

·         It is the heat developed by the welding machine at the weld joint to melt the weld metals.

·         Heat input is important parameter in the size and visual appearance of welding.

·         Heat is directly affect the micro crystal structure of the material which gives sound welding joint.

·         Welding strength is also directly depends upon the heat input.

·         So for sound welding joint quality it is necessary to calculate the welding machine efficiency in the form of heat input.

 STEPS

·         Before starting testing kindly check our welding machine is calibrated or not, if not then calibrate it properly.

·         Switch on the welding machine.

·         Start the welding by setting standard current and voltage on machine by moving knob as per the WPS.

·         Record the current and voltage value.

·         You may recheck the amperage and voltage by using Multi-meter.

·         If multi-meter value and welding machine display values are match then your welding machine is working properly.

·         Measure the welding length and time required to complete this welding length and noted it down.

·         Unit of heat input is Joules/mm.

·         Now apply the following formulas to calculate the heat input.

·         We know that Ohm’s law of electricity,

V =  I . R, where V-voltage in Volts, I- current in ampere, R-resistance in Ohm.

Travel speed 

 

1.    Heat input

 

Where,

·         V- Voltage in Volts,

·         I-current in Ampere,

·         Travel speed in mm/sec.

2.    Heat input

Where,

 

·         V- Voltage in Volts,

·         I-current in Ampere,

·         Travel speed in m/min.

3.    Heat input

Where,

 

·         I-current in Ampere,

·         R-resistance in Ohm,

·         t- Time required in sec to complete weld length.

·         L- Length of the weld in mm completed in time t.