postwelding heat treatment

[jcenter]

i am currently building dlm chassis's built mostly with 4130 moly with some d.o.m. and welded seam also,wall thickness's range from .065-.095.mig welding with millermatic 185. what would the temperature range be for heat treating the chassis after it has been welded.this would be done in an oven after the car has been removed from the jig

[ASKANDY]

Heat treating would have to be done in an oven controlled environment. Unless you know someone, this can be expensive. Heat treating also changes the parent metal strength, therefore reducing it's advantages. Stress relieving would be a better choice. Take a 900deg temp crayon and mark about 1 inch away from the weld joint. Heat the welded area with a neutral flame oxy/acetylene torch in a constant swirling motion to reduce "hot spotting". When the temp marker changes, move to the next joint.

Andy

[Sean Brown]

Andy,

Do any of the manufactures you deal with (sprint car, road race, drag or what have you) actually carry out this procedure?

Thanks,

Sean

[Kevin Disney]

Sean,

I know of one sprint car fabricator(Avenger)that has used postweld heat treatment, however they put the entire chassis in the a oven at about 1100 degrees F. Also, I have heard of some fabricators using vibratory stress relief, which is becoming more accepted by fabricators for weld conditioning and stress relief.

[JOHN R. TIPTON]

Heat Treating and Stress Relieving

I AM A CHASSIS BUILDER AND I ALWAYS STRESS RELIEVE MY WELDS ON CM TUBING, WITH A 900 DEGREEE HEAT (TEMP STICK) AND HAVE NEVER HAD A PROBLEM. HAVE HEARD SOME CHASSIS BUILDERS SAY "MY CAR WILL STRESS RELIEVE ITSSELF IN THE TRAILER GOING DOWN THE ROAD" I NEVER DID THINK THIS WASA GOOD IDEAS AND STILL STREESS RELIEVE WITH A ROSEBUD TORCH AND 900 DEGREE TEMP STICVK ABOUT AN INCH OR INCH AND QUARTER FROM THE WELD. HEAT TREATING IS NOT NECESSARY ON A MILD STILL CHASSIS. I ALSO USE E 70 S MILD STEEL ROD ON ALL MY CARS , MILD STEEL OR CHROMEMOLY AND HAVE NEVER HAD A PROBLEM.
GOOD LUCK AND I HOPE THIS WILL HELP YOU IN YOUR CHASSIS WORK

JOHN R. TIPTON