Re: [MW:13570] Decrease in bevel angle - Essentail variable as per Shell DEP

Welding Bevel angle is Provided for below reasons,

1. ACCESSIBILITY for the torch and electrode from the Root to the Cap.

2. DECREASE the Heat Conductivity along the bevel edges, more the bevel angle lesser the Heat conductivity

3. PROPER FUSION along the bevel edges, narrow the bevel will result in improper fusion(lack of side wall fusion)

4. BETTER FLOAWABILITY of the Liquid metal.

From the above it is clear that for some special materials like DSS, decrease in weld bevel will result in more conductivity and increased Heat input along the bevel edges and HAZ, may be one of the reason for its restriction.

 

Thanks & Regards J.Gerald Jayakumar 0091-9344954677

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From: N VENKATESWARA PRASAD <weldengr.velosi@gmail.com>
To: materials-welding <materials-welding@googlegroups.com>
Sent: Wednesday, January 25, 2012 10:06 AM
Subject: [MW:13564] Decrease in bevel angle - Essentail variable as per Shell DEP

Dear All,

As per  Shell DEP 30.10.60.18, the decrease in angle is essentail
variable.  What is concept behind it?  Is is applicable for  Compound/
composite angle joint design also.  As per this joint design up to 19
mm the bevel will be 37.5 degrees, later it will be only 10 degres.


My concept is the anlge is only for accessability and in case of DSS,
Nickel alloys higher anlge for  better wetting.  It should not
applicable for carbon steels.
Please debate on this.

The Clause as per DEP as given  below:


11.1 Add new clause 11.1.4 It is the Manufacturer's responsibility to
ensure that
welding operations are carried out in accordance with the
parameters as specified on the qualified WPS. Unless
otherwise specified by local regulations, welding procedures
shall be qualified in accordance with ISO 15607 and/or
ASME IX. Irrespective of the design code, welding procedure
qualifications shall be re-qualified when any of the following
conditions occur:
• Joints
- A change from double sided to single sided welding, or
vise versa (delete) but not the converse;
- A decrease in welding groove angle of more than 10
degrees.
• Consumables
- Any change of consumable classification;
- Any change in consumable brand name when corrosion
testing or impact testing is required;
- Any change in size of more then 1 mm of consumable in
the root run of single sided welds.
• Welding position
Change in welding direction (vertical up to vertical down
welding or vice versa).

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