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13 CR L80 – 80 Ksi Minimum Yield Strength

Specification of 13 CR L80 – 80 ksi Minimum Yield Strength


1.1 This specification pertains to 13% chromium stainless steel bar and tubing with a minimum yield strength of80 ksi. This material is often referred to as a 420type stainless steel with a restricted carbon range or a 420 modified. Tubular products meeting the requirements of API 5CT L80 13Cr meet the requirements of this specification. The 13% chromium stainless steel are used primarily for downhole applications where wet CO2 is present; this material, though listed in NACE MR0175/ISO 15156, has limited resistance to cracking in H2S containing environments.

1.2 When required by Purchase Order or Engineering Document, There are Supplement Requirements that are applicable and defined herein.


2.1 API 5CT:Specification for Casing and Tuing

2.2 ASTM A29: General requirements for Steel Bars, Carbon and Alloy, Hot-Wrought and Cold- Finished

2.3 ASTM A370: Mechanical Testing of Steel Product

2.4 ASTM E10: Test Methods for Brinell Hardness of Metallic Materials

2.5 ASTM E18: Test Methods for Rockwell and Rockwell Superficial Hardness of Metallic Materials

2.6 ASTM E165: Standard Practice for Liquid Penetrant Inspection

2.7 ASTM E709: Standard Practice for Magnetic Particle Inspection

2.8 NACE MR0175/ISO 15156: Petroleum and Natural Gas Industries – Materials for use in H2S Containing Environments in Oil and Gas Production

2.9 NACE TM0177: Laboratory Testing of Metals for Resistance to Sulfide Stress Cracking in H2S Environments


3.1 Chemical Composition: The chemical composition in weight percent shall meet the requirements listed in the Table below:

C Mn Si P S Ni Cr Cu
Min. 0.15 0.25 12.00
Max. 0.22 1.00 1.00 0.020 0.010 0.50 14.00 0.25

3.2 Mechanical Properties: The mechanical properties shall be determined at the mid radius location for bars and full wall (or mid-wall) sections for tube in accordance with ASTM A370 and shall meet the requirements listed in the Table below:

Yield Strength Ksi (MPa) Tensile Strength ksi (MPa) Elongation Reduction Of Area2 Hardness Rockwell C
Min. 80.0 (552) 95.0 (655) 16% 35.0%
Max. 95.0 (655) 120.0 (827) 23.0 (see note 3)
Note 1: Yield strength may be either the offset or extension methods. Generally, the 0.2% offset method is used for bars and 0.5% by extension method is used for tubulars. Yield strength for API 5CT 13 Cr materials shall be measured by 0..5%elongation under load.
Note 2: For tubular products, there is no requirement for reduction of area.
Note 3: For bar products (SS-303), the maximum hardness is 22.0 HRC.

3.3 Impact Toughness: A set of three Charpy V Notch tests shall be run in accordance at 32°F (0°C) or lower in accordance with the requirements listed herein for bar and tubular products.

3.3.1 Tubular products – Impact Toughness: A set of three Charpy V Notch tests shall be run in accordance with API 5CT AT 32°F (0°C) or lower. Not more than one of the three test specimens may exhibit an impact energy value less than the required average value as defined herein and in no case shall the value be below 2/3 of the required minimum average value. The use of sub-size specimens is not permitted without prior Engineering approval.

When possible by tube dimensions, the impact test shall run in the transverse direction. The minimum acceptable average impact value in the transverse direction shall be 15 ft-lbs (41joules) or in accordance with the following equation, whichever is greater

CVN Absorbed Energy in ft-lbs = 12.2t+5.1 Where t = thickness of tube at time of heat treatment

When transverse tests cannot be conducted, longitudinal tests shall be run and the minimum acceptable average impact value in the longitudinal direction shall be 30 ft-lbs (14 joules) or in accordance with the following equation, whichever is greater.

3.4 Melt Practice: Steels made to this specification shall be electric furnace melted, fully killed and ladle refined and/or vacuum degassed. The steel shall be produced using melt and refining practices proven capable of producing fine grained steels which are free from deleterious defects. The steel may be either ingot cast or continuous cast.

3.5 Heat Treatment and Condition: The steel shall be furnished in the hot worked and quenched and tempered condition. Bars shall have a minimum reduction ratio of 4 to 1. The minimum tempering temperature shall be 1200°F (649°C).

3.6 Straightness and Tolerances: Tubing shall meet the dimensional tolerances of API 5CT. For straightness, bars and tubing shall exhibit a chord height deviation of less than 0.2%.


4.1 Traceability: The heat identification shall be maintained through all stages of processing. The heat treat batch identities shall be maintained with the heat lot traceability.

4.2 Surface Quality: The bar shall be free cracks, laps, seams or other defects. Removal of surface defects to the limits of ASTM A29 for bar is acceptable.

4.3 Test Requirements: The test required with frequency are defined in the following Table:

Test Required Test Frequency Method & Acceptance
Chemical Composition Once per heat Paragraph 3.1
Tensile Properties Once per heat & heat treat batch As required by Paragraphs 3.2 or Supplement 10
Surface Hardness Once, each length or piece Paragraph 3.2
Impact Toughness One set per heat & heat treat batch As required by Paragraph 3.3 or Supplement 4 or 53
Volumetric Inspection 100% volumetric When required by Supplement 1
Electromagnetic Inspection 100% When required by Supplement 53
Surface NDE Inspection 100% machined surfaces When required by Supplement 3
Surface Inspection 100% visual on each bar Paragraph 4.2
SSC Testing One set per heat & heat treat batch When required by Supplement 7or 58

4.4 Reports: A material test report (MTR) shall be prepared for each heat of material. The test report shall contain be following minimum information: results of tests listed in Section 5.3, heat lot identification, heat treat batch/lot identification, statement of compliance to this specification, and Purchase Order Number. Laboratories not associated with product manufacturing shall perform the testing.