Military Welding Procedures

By - Date 09-27-2000 20:46

Does anyone have any experience writing and qualifying welding procedures for HY-80 to the Military Specification NAVSEA Technical Publication S9074-AQ-GIB-010/248. We are qualifying the SMAW process in the vertical position but we are supposed to limit heat input to a max. of 55,000 joules. This is easy to do during the testing since we are only using 1/8"OD electrodes but we need to know how to limit the heat input for each of the electrodes that we may be using. Do we simply list each electrode diameter and the minimum travel speed that it must be used at?

Thanks in advance for any help.

Howard

By - Date 09-30-2000 03:41

I am not familar with that specification but I have worked with HY-80 in accordance with Mil-STD 1688 and Mil-STD 248 and the procedures I used listed a minimum bead length for a given amount of electrode melt. They also indicated travel speeds at the nominal amperage/voltage. This may have all changed as this was about 10 years ago.

By MBSims

Date 10-10-2000 04:36

I had some old info on HY-80 welding to MIL-STD-1688 and MIL-STD-248 that had a 55,000 joules/inch maximum heat input. The heat input was controlled by limiting bead length for a 12 inch long SMAW electrode. The ranges were:

Diameter Bead Length per 12" Electrode Burn Off

3/32" 1-5/8" to 4-1/8"
1/8" 3-3/8" to 5-3/16"
5/32" 4-3/8" to 6-3/4"
3/16" 6-1/4" to 10"
7/32" 11-3/8" to 16-1/4" (14" burnoff)

The last two sizes are definitely not for the weak of heart!

The above would not be very practical if you wanted to use GTAW or FCAW. You could use the heat input formula to determine the minimum travel speed for each electrode size on your welding procedure. The formula is:

Heat Input (joules/inch) = (volts x amps x 60)/travel speed in inches/minute

Determine a reasonable maximum amperage and voltage for each electrode size and use 55,000 J/inch in the above formula to find the minimum travel speed for the welding procedure.

Example:

Rearranging the formula to find minimum travel speed,

Min. Travel Speed (inches/min) = (volts x amps x 60)/55,000

For a 3/32" electrode with a limit of 21 volts and 100 amps, the min. travel speed to keep heat input below 55,000 J/inch would be:

Min Travel Speed = (21 V x 100 A x 60)/55,000 = 2.3 inches/minute minimum

Just be careful that the minimum travel speeds you calculate are practical for the welder. You don't want to push the travel speed so high that you have narrow, ropey beads with poor fusion. Keep the current and voltage ranges practical too. Voltage is controlled manually by the welder's arc length and they will not want it to be so low that it is hard to see the puddle and the puddle does not flow well. Talk to the welders and find a happy medium.

Hope this helps.

Marty Sims

By - Date 10-12-2000 22:15

I have an application that does Heat input calculations along with some other stuff. It's not fancy but you may find it useful. Its the VB 2.0 version at. Its free unless you just feel the need to send me money:)

http://www.geocities.com/pipewelder_1999/index.html?971387766870