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 PressureVessels for High Temperature, HighPressure Hydrogen ServiceAPI.
Tensile strength shall not exceed the following limits:
a. Conventional steels: 100 ksi (690 N/mm2)
h. Advanced steels: 110 ksi (760 N/mm2)
Yield strength shall not exceed the following limits:
a. Conventional steels: 90 ksi (620 N/mm2)
b. Advanced steels: 90 ksi (620 N/mm2)
5.5.2.2 Elevated temperature tensile tests, when required by the purchaser, shall he performed at the equipment design temperature. Test specimens shall he in the maximum PWHT condition. Acceptance values shall he as specified by the owner/user.
5.5.3 Impact Properties
5.5.3.1 Average impact values at —20°F (—29°C) of three Charpy V-notch test specimens heat treated in accordance with 5.5.1.2 shall not be less than 40 ft—lb (55 J) with no single value below 35 ft—lb (47 J). The percent ductile fracture and lateral expansion in mils shall also be reported.
5.5.3.2 Step Cooling Tests
5.5.3.2.1 Prior to the start of fabrication, step-cooling tests shall be performed on each heat of base metal to determine its susceptibility to temper embrittlement. unless waived by the purchaser.
Two sets of Charpy V-notch test specimens, with a minimum of 24 specimens per set, shall be prepared and subjected to the following heat treatments:
Set 1 —Minimum PWHT only, to establish a transition temperature curve before step cooling.
Set 2—Minimum PWHT plus the step cooling heat treatment specified in 5.5.3.2.3, to establish a transition temperature curve after step cooling.
5.5.3.2.2 Step cooling heat treatment shall be as follows:
1. Heat to 600°F (316°C), heating rate not critical;
2. Heat at 100°F (56°C)/hour maximum to 1100°F (593°C);
3. Hold at 1100°F (593°C) for 1 hour;
4. Cool at 10°F (6°C)/hour maximum to 1000°F (538°C);
5. Hold at 1000°F (538°C) for 15 hours;
6. Cool at 10°F (6°C)/hour maximum to 975°F (524°C);
7. Hold at 975°F (524°C) for 24 hours;
8. Cool at 10°F (6°C)/hour maximum to 925°F (496°C);
9. Hold at 925°F (496°C) for 60 hours;
10. Cool at 5°F (3°C)/hour maximum to 875°F (468°C);
I I. Hold at 875°F (468°C) for 100 hours:
12. Cool at 50°F (28°C)Ihour maximum to 600°F (3 16°C);
1 3. Cool to ambient temperature in still air.
5.5.3.2.3 After the Charpy V-notch test specimen sets are heat treated, each set of specimens shall be impact tested at eight selected test temperatures to establish a transition temperature curve. One of the tests shall he performed at —20°F (—29°C). Three specimens shall be tested at each test temperature. The transition temperature curve shall be established from at least two test temperatures on both the upper and lower shelf and a minimum of four intermediate test temperatures.
5.5.3.2.4 The 40 ft-lb (55 J) transition temperatures shall be determined from the transition temperature curves established from the two sets of Charpy V-notch spedmens. The impact properties shall meet the following requirement:
CvTr4O + 2.5 DCvTr4() £ 50°F (10°C), where
CvTr4O = 40 ft-lb (55 J) transition temperature of the base metal subjected to the minimum PWHT only.
DCvTr4O = the shift of the 40 ft-lb (55 J) transition temperature of material subjected to the minimum PWHT plus the step cooling heat treatment.
6 Welding Consumable Requirements
6.1 MATERIAL REQUIREMENTS
6.1.1 The deposited weld metal, from each lot or batch of welding electrodes and each heat of filler wires, and each combination of filler wire and flux, shall match the nominal chemical composition of the base metal to be welded.
6.1.2 The following chemical composition limits shall be controlled to minimize temper embrittlement.
Cu: 0.20% maximum
Ni: 0.30% maximum
6.1.3 Low hydrogen welding consumables, including fluxes, having a maximum of 10 ml of diffusible hydrogen for every 100 grams of weld metal, per AWS A4.3, shall be used. They shall be baked and stored in accordance with manufacturer’s instructions, i.e., electrode oven, to reduce moisture content and to ensure their low hydrogen nature.
6.2 MECHANICAL PROPERTIES
6.2.1 Tensile Properties
The tensile properties of the deposited weld metal shall meet those of the base metal in accordance with 5.5.2.