ASTM A789 UNS S32760 Tubing

General Introduction

Seamless SDSS tubing made from ASTM A789 UNS S32760; O.D. = 25.4 mm, W.T. = 1.65 mm (min.), L = 7400 mm.

The tubing made form ASTM A789 UNS S32760 is a super duplex stainless steel (SDSS) tube. UNS S32760 has guaranteed corrosion performance with the PREN value no less than 40. Similar to UNS S32750, it has excellent resistance to chloride stress corrosion cracking (SCC) and pitting corrosion; it also has much higher strength than the austenitic stainless steels and better impact toughness than ferritic stainless steels. ASTM A789 UNS S32760 tubing is generally furnished with actual outside diameter, minmum or average wall thickness. They are primarily used for services requiring general corrosion resistance, with particular emphasis on resistance to SCC. The tubing are susceptible to embrittlment if used for prolonged periods at moderately elevated temperature. UNS S32760 has a proprietary brand name of “Zeron 100”.

UNS S32750 vs. UNS S32760

Generally, UNS S32750 and S32760 can be viewed as two different ways to reah the same level of corrosion resistance and mechanical properties. In most cases, they are interchangeable. However, there are some subtle differences. UNS S32760 has deliberate addition of copper and tungsten elements to control the ferritic-austenitic phase balance and to impart certain corrosion resistance. Copper is an austenite-stabilizing element, while tungsten is a ferrite-stabilizing element. The addition of copper to duplex stainless steels produces alloy that can be precipitation hardened to higher strength and hardness. The copper content also impart enhanced resistance to corrosion in many nonoxidizing and mineral acids such as hydrochloric acids and dilute sulfuric acids. The addition of tungsten improves the strength and the resistance to pitting corrosion.

Chemical Composition Requirements

Tensile & Hardness Test Requirements

Manufacture & Heat Treatment

The solution annealing of S32760 tubing in furnace.

ASTM A789 S32760 seamless tubing shall be made by a hot-rolled and cold-drawn combined process. The welded tubing shall be manufactured by a plasma arc welding (PAW) or gas tungsten arc welding (GTAW/TIG) process with no filler metal added. After hot- or cold-finished, the tubing shall be solution annealed at a temperature between 1960-2085°F [1070-1140°C], followed by the rapid cooling in water.

Testing & Inspection

Tension test, flaring test for seamless tubes, flange test for welded tubes, hardness test, reverse flattening test for welded tubes, ultrasonic test, X-ray inspection, dimensional inspection, visual examination, eddy current test.

Permissible Variations (Tolerances) in Dimensions