Heat input and travel speed

[moe27]

When qualifying a weld procedure we take note of the amps, volts and travel time for each pass.
When the coupon is finished we may have travel speeds ranging from 7" to 10" per minute. How do you calculate the travel speed for the WPS, average all the speeds, take a high and a low average or take the slowest travel speed which will result in the greatest heat input???

Regards,

moe27

 

[david339933]

Travel Speed should be a range. I'm sure the amps and volts have a range, so the only way to ensure heat input is under the max. allowable is to increase/decrease travel speed.

 

[Don56]

Moe27, you are on the right track. The ranges you provide on the WPS should be based on the values used during the welding of the PQR coupon. The ranges you provide are for guidance to the welder. Heat input only comes into play as a supplementary variable (QW-409.1) when impact testing is required. QW-409.1 requires requalification if more heat is input than was input during qualification, so if you want to limit heat input reference a maximum heat input.

 

[moe27]

So Don56, I should use the slowest travel speed and post the max heat input from the PQR on the WPS which will give me more grace (higher heat input) as far as not exceeding the max heat input in production, am I understanding correctly??

Thanks,

moe27

 

[Don56]

Check the heat input from each pass on your PQR. The highest is the max heat input limitation on the WPS. Amps, Volts, and Travel Speed should all be ranges. I know that few welders ever calculate what the heat input will be using certain amps volts & TS, but you do not want to handicap them by limiting the TS to one value. They would be out of compliance with the procedure if they varied from that one value.