Regarding the welding coefficient

It does not refer to the gap that should be left between two welded parts during welding

The weld joint coefficient φ refers to the ratio of the strength of a butt weld joint to the strength of the base material. It is used to indicate the degree to which the strength of a welded joint is reduced due to factors such as welding materials, welding defects, and residual welding stresses, and it represents a comprehensive reflection of the mechanical properties of the welded joint. The welding joint coefficient φ should be determined based on the welding process characteristics of the welded joints in the pressure-bearing elements of the container (single-sided welding or double-sided welding) ； Determined by the presence or absence of shims) and the length proportion for non-destructive testing.

There is no welding coefficient; it should be the welding joint coefficient. The weld joint factor ф shall be determined based on the type of weld joint in the compressed member and the length proportion of non-destructive testing. Note: The welding joint coefficient is sometimes referred to as the weld coefficient, which is the ratio of the strength of the weld to the strength of the base material. Double-sided welded butt joints and fully penetrative butt joints equivalent to double-sided welding: 100% non-destructive testing, ф = 1.00; local non-destructive testing, ф = 0.85. Note: Fully penetrative butt welds equivalent to double-sided welding refer to welds that are formed on both sides but welded from only one side, and are evaluated as if they were double-sided welds (including evaluation of the welding test pieces), such as welds with TIG welding for backing or welds using ceramic or copper liners. Single-sided welded butt joint (with gussets in close contact with the base metal along the entire length of the weld root): 100% non-destructive testing, ф = 0.9; local non-destructive testing, ф = 0.8. Note: It should be noted here that 1) this is a butt joint ； 2) Fully penetrated structure ； 3) There are gussets in close contact with the base metal along the entire length of the weld root. There is no consensus on what constitutes a tightly fitted gasket; generally, the welding procedure qualification serves as the standard.

Regarding the welding joint coefficient, look for relevant reference materials – it is generally covered there, with fairly good explanations as well.

If you are referring to pressure vessels, the welding joint factor φ is primarily related to the rate of non-destructive testing: if φ = 0.85, it indicates 20% RT testing; if φ = 1, it indicates 100% RT testing. The welding joint factor represents the ratio of the strength of the butt-welded joint to the strength of the base material!

Hehe, everyone is so wise; thanks

This is the most basic knowledge; anyone working with pressure vessels must be very familiar with it.

The welding joint coefficient is the multiple by which the strength of the welded joint corresponds to that of the base material; it ranges up to 1. To understand this properly, refer to GB150

The weld joint coefficient φ refers to the ratio of the strength of a butt weld joint to the strength of the base material. It is used to indicate the degree to which the strength of a welded joint is reduced due to factors such as welding materials, welding defects, and residual welding stresses, and it represents a comprehensive reflection of the mechanical properties of the welded joint. The welding joint coefficient φ should be determined based on the welding process characteristics of the welded joints in the pressure-bearing elements of the container (single-sided welding or double-sided welding) ； Determined by the presence or absence of shims) and the length proportion for non-destructive testing. Baidu also makes it very clear – don’t be too lazy, original poster on floor 3

The weld joint factor refers to the strength reduction factor of the weld metal in the butt joint of the vessel shell relative to the base material.

But a beginner like me doesn’t know the welding type of the container or the length for non-destructive testing – so how can I determine the welding coefficient?