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[MW:1275] Fwd: Material for re-bars

By Materials & Welding
Dear All,
 
Waiting for your inputs.
 
Regards
Sharif

---------- Forwarded message ----------
From: Mahtab Dewan Sharif <sharifmahtab@gmail.com>
Date: Nov 2, 2008 12:58 PM
Subject: Re: Material for re-bars
To: materials-welding@googlegroups.com

 
Sorry, I forget to attach the specification.
 
BR
Sharif


 
On 11/2/08, Mahtab Dewan Sharif <sharifmahtab@gmail.com> wrote:

Hi all,

Can you please advice us on the suitable welding Process and Electrode for the following query as requested below

 

Sharif.

------------------------------------

Dear Sir:

A consignement of cut re-bars 12m, 16mm, 20mm, 25mm, 32mm each of the sizes of 800mm length x 12 nos each were sent to your office this morning from our Dhaka office.

 

The bars are quenched and tempered [Q & T] type which means it heat treated and has a relatively hard outer martensite layer and a soft ferrite-pearlitic core. Typical steel composition and mechanical strength properties are attached. The steel composition is relatively insensitive to welding.

 

As discussed in an earlier meeting with you the bar samples have to be spliced welded at a lap length of 8D which means 8 times the bar diameter. Example: A 20mm bar will be lapped at 20mm X 8 = 160mm.

 

Further, care must be exercised to alternatively weld the bar sides so that the entire bar body is not overheated over 580 dgrees celsius. This is the recrystallization temperature for martensite.

 

Selection of the correct electrode type to develop rupture strength beyond the tensile strength of the Xtreme500W bars is the objective of this testing exercise. Bar failure should be away from the bar lapped area so that sufficient ductility is exhibited in bar fracture. Please let me know the welding procedures to be adopted at your w-shop 

 




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