asme sa240 uns s41500 quenching and tempering data

ASME SA240 UNS S41500 Quenching and Tempering Data

ASME SA240 UNS S41500, a martensitic stainless steel also known as F6NM or AISI 415, is specified for plates, sheets, and strips used in pressure vessels and general applications where high strength, good toughness, and moderate corrosion resistance are required.

This grade is heat-treatable, with quenching and tempering being the primary processes to achieve its optimal mechanical properties, such as tensile strength of 795 MPa min, yield strength of 620 MPa min, and elongation of 15% min.

 Quenching and tempering enhance the material's martensitic structure, improving hardness (up to 32 HRB max) while maintaining ductility and resistance to environments like sour gas (NACE MR0175 compliant when properly treated). As a producer, Gangsteel ensures our SA240 UNS S41500 stock (1-200mm thick) undergoes precise heat treatment for consistent performance.

Heat Treatment Process Overview

Under ASME SA240, UNS S41500 is typically delivered in the quenched and tempered (QT) condition to meet the specification's mechanical requirements. The process involves annealing (optional for softening), quenching to form martensite, and tempering to relieve stresses and adjust properties. Tempering is often done in single or double stages for optimal results, especially for thicker sections where uniformity is critical. Avoid temperatures between 425-540°C to prevent embrittlement.

Recommended Quenching and Tempering Conditions

Based on standard practices for UNS S41500 (aligned with equivalents like EN 1.4313), the following conditions are used for QT delivery states. These ensure compliance with ASME SA240's mechanical specs.

• Annealing (Optional, Condition +A): 600-650°C, air or furnace cooling – Used to soften the material for machining (hardness ~235-295 HB).
• Post-Weld Heat Treatment (PWHT): For welded plates, temper at 580-620°C for 5-30 minutes to restore properties and reduce hardness in the heat-affected zone (HAZ) to ~314-322 HV, improving toughness to ~115-118 J. Heating rates: 10°C/s for short holds, 150°C/h for longer.
• Forging/Rolling (Initial Processing): 1150°C, air cooling – Ensures workability before final QT.

These processes result in a microstructure of martensite laths with retained austenite, optimizing for ASME requirements. For NACE compliance, ensure final hardness <22 HRC (converted from HRB). Gangsteel's SA240 stock is QT-treated for immediate use, with custom conditions available.

Effects of Quenching and Tempering

• Quenching: Rapid cooling forms martensite, increasing hardness but potentially brittleness; oil/air minimizes distortion in plates.
• Tempering: Relieves stresses, improves ductility; double tempering (as in QT650) enhances austenite retention for better toughness (e.g., from ~300 HV post-quench to ~320 HV tempered).
• Simulation Data: Thermal cycles at 1000-1350°C (12s cooling) mimic welding HAZ; PWHT at 620°C/30min achieves base metal properties.

For sourcing ASME SA240 UNS S41500 (1-200mm stock, $2,600-2,800/ton FOB), contact Gangsteel—we provide treated material with full certs.