WELDING RESPONSIBILITY
Each employer is responsible for the welding done by the personnel of his organization and shall conduct the tests required to quality welding procedures and to quality and as necessary re-qualify welders and welding operators.
WELDING QUALIFICATIONS
Welders and welding operators must be qualified to ASME Section IX, except as modified by B31.3. The general details are listed in this section. Special attention should be given to subparagraph f, allows Table A-1 when matching P- and S-Numbers.
PROCEDURE QUALIFICATION BY OTHERS
a. Each employer is responsible for qualifying any welding procedure that organization’s personnel will use, subject to the specific approval of the inspector.
b. The inspector shall be satisfied that:
i. the proposed WPS has been prepared, qualified and executed by a responsible, organization with expertise in the filed of welding procedure.
ii. The employers has not made any change in the welding procedure.
PERFORMANCE QUALIFICATION BY OTHERS
a. To avoid duplication of effort, an employer may accept a performance qualification designed for another employer, provided the inspector specifically approves.
b. Acceptance is limited to qualification on piping using the same procedure wherein the essential variables are within the limits in Section IX.
QUALIFICATION RECORDS
The employer shall maintain a self-certified record, available to the inspector of procedures and welders employed.
WELDING REQUIREMENTS
a. Welding shall be made in accordance with a qualified procedure and be qualified welders or welding operators.
b. Each welders shall be assigned an identifying symbol. The welds shall be marked or appropriate records kept.
c. Tack welds shall be made with the filler metal equivalent to that used in the root pass and made by a qualified welder. Tack welds shall be fused with the root pass, cracked and bridge tacks shall be removed.
d. Peening is prohibited on the root and final pass of a weld.
e. No welding shall be carried out if rain, snow, sleet or excessive wind, occurs and the weld ares frost or wet mixture.
PRE-HEATING (330)
a. Used to minimize the detrimental effects of high temperature and severe thermal gradients inherent in welding.
b. Minimum recommended preheat temperatures are given in Table 330.1.1.
c. If the ambient temperature is below freezing, the recommendations in Table 330.1.1 become requirements.
d. Preheat zone shall extend at least 1 inch beyond each edge of the weld.
POST WELD HEAT TREATING (331)
a. Used to avert or relieve the detrimental effects of high temperature and severe temperature gradients inherent in welding and to relieve residual stresses created by bending and forming.
b. General heat treatment requirements include Table 331. 1. 1 (thickness and material grouping ranges) and must be specified in the WPS.
c. PWHT zone shall extend at lest 1 inch beyond each edge of the weld.
LET’S PRACTICE!
- Determine the minimum pre-heat temperatures:
a) 0.5″ thick, P-1 material?
b) 2.0″ thick, P-3 material, SMTS 60 ksi?
c) 1.0″ thick, P-3 material, SMTS 70 ksi?
2. A P-1 material (carbon steel) 2″ thickness is being PWHT. What is the:
a) Holding temperature?
b) Minimum holding time?
