Effects of oxyacetylene torch cutting bolts on structural member

[aumechengr]

I was wondering what the mechanical property effects, if any, there would be in using an oxyacetylene torch to cut rusted bolts from a structural member. The structural member is made from ASTM A 572 Grade 50. The bolts are ASTM A 490 Type 3, nuts ASTM A 563 DH3 and washers ASTM F 436. Overtime the fasteners have rusted and need replaced. Our maintenance personnel want to use a oxyacetylene torch to cut the bolts versus using an impact wrench to save time. I do not think that there would be any adverse effect to the mechanical properties due to the increase in temperature from cutting the bolts, but I do not have much experience in this area. Any helpful advice would be appreciated.

aumechengr

 

[metengr]

aumechengr;
As long as your maintenance personnel are proficient at using a cutting torch, I see no harm in affecting the bulk mechanical properties of the structural member. You may want to caution the folks to keep the cutting flame off of the steel structural member as much a possible. Also, you will need to go back and clean/ream the affected holes.

 

[unclesyd]

With washers and as stated above a good operator with the proper tip there should be no problems. With a washer the steel should see no mark.

Here is one reference.

http://www.aisc.org/MSCTemplate.cfm...tomSource/Faq/SteelInterchange.cfm&FaqID=1975

 

[Metalguy]

Tell your maint. man that if he has a big enough impact wrench, it will be far faster to use that. A big wrench will either spin the nut off in a second or simply twist it right off if it's rusted tight.

I have a 1" drive gun that loves to do just that, instantly. There are far bigger guns available, some are hydraulic.

Gold is for the mistress - silver for the maid
Copper for the craftsman cunning in his trade.
"Good!" said the Baron, sitting in his hall
But iron - cold iron is the master of them all.
Rudyard Kipling

 

[aumechengr]

I had originally suggested using the impact thinking the same thing. But, due to the location of the structure it will be easier to use an oxyacetylene torch. Thanks to all who provided input and to unclesyd for the reference link.

 

[Rjeffery]

At lease they will not be able to clean grease and REUSE them!

The best way to test something is to squeeze it, slowly, until it breaks!