API RP 934:2000 pdf download

API RP 934:2000 pdf download.Materials and Fabrication Requirements for 2-1/4Cr-1Mo & 3Cr-1Mo Steel Heavy Wall Pressure Vessels for High Temperature, High Pressure Hydrogen Service.
7.2.3 Production Testing of Base Metal Welds
7.2.3.1 Chemical Composition of Production Welds
7.2.3.1.1 The chemical colupositlon ol the wcld deposit representing each ditkrcnt welding procedure shall be checked by either laborato,y chemical analysis or by using a portable analyzer of equivalent accuracy and precision.
7.2.3.1.2 The chromium, molybdenum. vanadium and columbium content tas applicable) of the weld deposits shall be within the ranges specified in ASMI3 Section II. Part C for the specified electrodes.
7.2.3.2 Hardness of Weld Deposit and Adjacent Base Metal
7.2.3.2.1 Alter final PWHT (see 74), hardness detenninafinns shall be made for each pressure-retaining weld using a portable hardness tester.
7.2.3.2.2 The hardness test results shall be the average of three readings and shall be taken in the weld metal and adjacent base metal.
7.2.3.2.3 Hardness values shall not exceed:
a. Conventional stls: 225 lIB, or equivalent
h. Advanced steels: 235 FIB, or equivalent
7.2.3.2.4 Hardness tests shall be performed on each 3- meter length of weld, or fraction thereof, and on the side exposed to the process environment, when possible.
7.2.3.3 Weld Impact Tests
7.2.3.3.1 Production test plates subjected to the minimum PWHT shall meet Article T-2 of the ASME Code. Additional production test plate material subjected to the maximum PWHT shall also be tested and shall meet the requirements of Article T-2. The impact test temperature and acceptance ciiteria shall be in accordance with 5.5.3.1.
7.2.3.3.2 Production test plates subjected to the minimum PWI-IT shall he impact tested before and after step cooling in accordance with the requirements of 5.5.3.2. unless waived by the purchaser.
7.3 WELD OVERLAY
The following special requirements shall apply:
7.3.2 Disbonding Tests
7.3.2.1 When required by the owner/user, a method to evaluate the weld overlay for susceptibility to hydrogen disbonding shall be agreed to between the t.tbricator and owner/ user. The owner/user shall define testing requirements and acceptance criteria. An example of a standard disbonding test may be found in ASTM G 146. As a minimum, the test shall represent actual operating conditions (hydrogen pressure, temperature and cooling rates) to which the equipment will he subjected during service.
7.3.2.2 Results of disbondini tests shall be available, prior to tibrication, for each welding procedure to be used on the vessel shell rings and heads. Previously qualified disbonding tcsL results can be submitted for review by the owner/user if representative of the proposed WPS and operating conditions.
7.3.3 Weld Overlay Procedure Qualification
7.3.3.1 The selected weld overlay process and the number at layers shall he qualified in accordance with ASME Section IX.
7.3.3.2 Procedure qualification tests shall he made on base metal of the same ASMI specification as specified for the vessel, but either plate or forging may be used. Thickness of the test specimen shall no be less than one half the thickness of the vessel base metal or 2 in. (54) mm.). whichever is less. The welding electrode, wire and flux used for the weld overlay procedure qualification shall be the same type and brand to be used in production.
7.3.3.3 The qualification test plates shall he sub ected to the maximum PWHT condition.
7.3.3.4 The chemical composition of the weld overlay shall be checked by chemical analysis of samples taken at minimum thickness qualified in accordance with Figure QW462.5(a) of the ASME Code. Section IX. It shall meet the filler metal specification for the final layer. The chemical composition, determined by these samples. should be used to calculate the ferrite content which shall be between 3 FN and
1OFN.
7.3.4 Preheat and Heat Treatments During Weld Overlay
Base metal shall be preheated in accordance with 7.2.2.1 for the first layer of weld overlay.