C2024-20958 Sulfide Stress Cracking Resistance Of Quenched And Tempered 41XX Low Alloy Steels With 26 HRC Max Hardness

Karthik Krishnan, Cheng Lum - Section A.2.2.3.3 and Table A.3 of NACE MR0175/ISO 15156-2 allows for use of 41XX type low alloy steels quenched and tempered in the tubular form if the hardness does not exceed 26 HRC for all temperature, all region sour service similar to the sour service guidelines of API 5CT/ISO 11960 L80 Type 1 and T95 Type 1 grades. While the clause recommends qualification for use in sour service it does not mandate the same. In this work different 41XX grades heat treated in tubular form to 26 HRC max hardness with varying quench and temper treatments were tested for Sulfide Stress Cracking (SSC) resistance to verify the clause. It is shown that only specific 41XX grades with certain quench and temper heat treatments could pass SSC testing prescribed for all region, all temperature sour service in NACE MR0175/ISO 15156. Hence qualification for use of this Section A.2.2.3.3 should not be optional but required else could lead to use in conditions where the material