API Standard 6A718 Inclusion of Additional Alloy 718 Strength Classes – J une Update - PowerPoint PPT Presentation

API Standard 6A718 Inclusion of Additional Alloy 718 Strength Classes – June Update

Acceptance of alloy 718

at 140 ksi min yield strength

Rashmi Bhavsar

Global Materials Métier Manager

Schlumberger

June 2012

• Background
• Inclusion of 718 -140
• Corrosion testing

Background

• 718 -120 ksi - API Standard 6A718, 1st and 2nd Editions
• 718-140 ksi - need for inclusion
• Heat treatment and microstructure discussed last meeting

• The 140 KSI grade cannot simply be added in this manner. It will require aging temperature to be changed from 1425 - 1475 F to 1400 -1475 F for 140 grade.
• The yield strength range will be 140 to 150 ksi (the current spec limits the yield strength to 145 ksi max for 120 grade)
• 40HRc max remain for now (Future 43 HRc max – NACE approval will require)

• A Ballot in 1982 from various suppliers and Shell Development to change hardness to 40HRC max
• Hardness up to 45HRc and YS up to 165 ksi
• Most data were at 750 and 1670F

Testing also successful at extremely high H2S/CO2 at 350 and 450 F – No cracks

(30 days test)

Courtesy : Schlumberger

500 Psi H2S, 500 psi CO2, 25%NaCl at 500oF

144 ksi actual yield strength at room temp – 100% stress level for six months

Courtesy: Foroni Metals

• With 40 HRc Max per Current MR0175 – min 3 heats
• Perform 90 days four point bent beam or c-ring

Or

Perform 30/90 days creviced bent beam or c-ring

• Perform SSRT in duplicates for information and ranking
• Test 140 and 150 ksi actual yield strength
• Test environment
• NACE level 6 (500 psi H2S, 500 CO2 and 121,300 mg/l cl at ) 350F)

Or

• H2S per NACE limits at 350F

Approximate cost $90 to 100K

• Supported the validation testing idea
• Testing required for Hydrogen Embrittlement
• Recommendation for SSRT with hydrogen charging by Total

or

• perform alternate testing - Uniaxial notched tensile test with hydrogen charging
• Testing procedure information being collected.
• Higher temperature testing recommended

• Test 718-140 ksi(actual close to 150 ksi) along with 718-120 ksi (actual 140 ksi )
• Perform 90 days 3” C-ring in duplicate from 3 suppliers min. (possibly 5)

H2S-500 psi, CO2-1000 psi, Cl -180,000 ppm at 400F

• SSRT – the same environment
• Hydrogen embrittlement test – TBD
• Quotes from three labs to be collected