Carry Over From API SC6 Winter Meeting API Standard 6A718 Inclusion of Additional Alloy 718 Strength Classes

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Carry Over From API SC6 Winter MeetingAPI
Standard 6A718 Inclusion of Additional Alloy 718
Strength Classes

• Tim Haeberle
• 30 June 2011

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Inclusion of Additional Alloy 718 Strength Classes

• Background
• API Standard 6A718, 1st and 2nd Editions, have
  included only one strength class 120K
• A 120 KSI min yield strength is what has been
  historically required for Alloy 718 tubing
  hangers
• The 120 KSI min yield strength exceeds the 75 KSI
  design criteria applicable to valve gates, seats
  stems
• API Standard 6A718 was developed to supplement
  the existing requirements of API 6A and ISO
  10423, and it is still meeting that objective.
• However..

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Inclusion of Additional Alloy 718 Strength Classes

• Background - Continued
• Although intended for API 6A equipment, API 6A718
  has now been specified for other types of oil and
  gas production equipment, such as down-hole
  safety valves
• The manufacturers of down-hole safety valves
  specify Alloy 718 with minimum yield strengths
  of
• 120 KSI
• 130 KSI
• 135 KSI
• 140 KSI
• While the 130, 135, and 140 KSI grades exceed the
  mechanical property requirements of API 6A718 and
  therefore comply with the mechanical property
  requirements of API 6A718, there can be other
  spec compliance problems.

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Inclusion of Additional Alloy 718 Strength Classes

• Background Continued
• The 135 and 140 KSI grades typically need to be
  precipitation hardened at a lower temperature
  than permitted by API 6A718, thereby rendering
  material heat treated in this manner out of
  compliance.
• Material in the 135 and 140 KSI grades is
  frequently hand picked from vendor inventory
  since it is difficult to achieve these strength
  levels while still meeting the NACE MR0175 / ISO
  15156 hardness limit of HRC 40.

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Inclusion of Additional Alloy 718 Strength Classes

• There have been requests to include the 130, 135,
  and 140 KSI strength classes in API 6A718.
• The 130 KSI strength class could simply be added
  as another strength class without having to make
  any other changes.
• The 135 KSI and 140 KSI strength classes cannot
  simply be added in this manner.
• The 135 KSI and 140 KSI strength classes would
  require testing and evaluation of the
  environmental cracking resistance of each grade,
  if heat treated using a precipitation hardening
  temperature or time outside of the ranges
  specified in API 6A718.
• Additionally, there needs to be a review to
  determine if the 135 KSI and 140 KSI strength
  classes are actually commercial grades, or if the
  requirement for hand picking material from
  inventory makes them too special inclusion in an
  API standard.

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Inclusion of Additional Alloy 718 Strength Classes

• Proposal
• Establish a small Work Group for Inclusion of
  Additional Alloy 718 Strength Classes
• Alloy 718 manufacturers and suppliers
• Equipment manufacturers using the alternate
  classes
• End users
• Work Group Objectives
• Define the differences in processing required for
  each of the alternate Alloy 718 strength classes
• Propose detailed qualification requirements for
  evaluating the alternate Alloy 718 strength
  classes that must be heat treated at temperatures
  or times that do not comply with the existing API
  Standard 6A718

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API CSOEM SR3 Form

• Form ready for submittal
• Requesting 100,000

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End Of Presentation