What is the minimum distance between welds?
The minimum distance between these two joints should be the one-time diameter of the pipe. So, if your pipe is 4″ NPS the distance should be 4″. If this is not possible, it should not be less than 1½”.
What are the standard requirements on the proximity of welds?
BS 2633 ‘Class I arc welding of ferritic steel pipework for carrying fluids’ (Section 11), states that the toes of adjacent butt welds shall, whenever possible, be no closer than four times the nominal thickness of the pipe.
What is weld toe?
Toe– The junction of the weld face and the base metal. Leg– The distance from the joint root to the toe of the weld. Face– The exposed surface of a weld on the side from which welding was done. Theoretical Throat– The minimum distance minus any reinforcement between the joint root and the face of a fillet weld.
What is a girth weld?
Girth welds are the different types of arc welding processes applied in the joining of two pipes along the circumference during a phase construction of a pipeline depending on the ease of implementation and the environmental factor. They are used in making circumferential welds in pipeline and underground systems.
What is a pressure retaining weld?
A typical pressure retaining weld joint may consist of three components: root pass, intermediate pass and final pass or “cap.” In many cases it is common that inspection hold points are established during the welding process to verify the integrity of in-process fabrication between welding passes.
How do you determine root gap in welding?
Root gap should not exceed 1/16-in. Fusible metallic backing is also used with this preparation with a root gap of at least 1/8-in. The single-Vee groove butt joint with root face and without external backing is also used for two pass welds where plate thickness exceeds 5/8-in.
How far apart are the pieces at the root of the weld?
Therefore, the root face for GMAW is often 1/16″–3/32″ (1.6 mm–2.4 mm). The root opening is 3/32″–1/8″ (2.4 mm–3.2 mm) and sometimes even a little wider.
Which welding is used for pipeline?
arc welding techniques
Pipe welding uses arc welding techniques, including shielded metal arc welding (SMAW), gas metal arc welding (GMAW) – including both MIG and MAG welding, flux-cored arc welding (FCAW), submerged arc welding, and tungsten inert gas (TIG) welding.
What is a longitudinal weld?
Longitudinal welding is a special type of welding technique used in pipe production applications wherein the finished products need an exceptionally high wall thickness because of the high internal or external pressures.
What is the minimum distance between welds in a pipe?
Marty is right. There’s no Code requirement for the minimum distance between welds. A figure “pulled off the air” that is very used in prefabricating shops and jobsites is that the minimum distance should be three times the pipe diameter.
What is the distance between two weld seams required by ASME?
ASME B31.3 or ASME Section VIII doesn’t specify any requirements related to the distance between two weld seams. The rationale is simple, welding is an integral part of the pipeline joining.
What is the minimum distance between adjacent butt joints/welds?
There is no minimum distances between adjacent butt joints/welds to my knowledge in B31.1 or B31.3. When I have encountered such restrictions, they were imposed by the contractor. It is usually easier to tell a welder that “it” is a code requirement than to explain the company’s position or philosophy of imposing such requirements or restrictions.
Is minimum distance between girth welds a code requirement?
Minimum distance between girth welds is usually covered in the fabrication or installation specifications and is not a code requirement. If you want to add a weld not shown on the isometric drawing, you usually have to get the approval of the piping designer since it may affect the piping stress analysis. Marty is right.