Multimet N155

Multimet N155 (UNS R30155) is a nickel-based alloy used predominantly in applications requiring strength, high temperature, and oxidation resistance. Multimet N155 can be treated to exponentially improve its temperature resistance and make it the perfect metal for tail pipes and cones, nozzles, and both turbine and afterburner components. Multimet N155 is composed primarily of Nickel and Chromium and standard specifications include AMS 5532, AMS 5768 and more.

At Rickard Specialty Metals, we have 30+ years of supplying Multimet N155 forgings to your custom measurements and shapes. Our forging process includes open die forgings, ring rolling and more. See below for a list of common Multimet N155 forged shapes, including round and flat bar, and additional product forms we offer.

Multimet N155 Additional Information:

Physical Properties

Hardness: Per AMS 5769 hardness is 156 to 217 HB in the solution heat treated condition for Multimet N155 bars and forgings, and 156 to 241 HB max for flash welded rings.
Density: 0.298 lbs per cubic inch.
Modulus of Elasticity: 29.3 MSI.
Coefficient of Expansion: 8.8 x10-6 in/in/F RT-800F. 9.7 x10-6 in/in/F RT-1400F.

Machining

Multimet N155 machining can we performing by conventional methods. Carbide tools should be used, however if these are not available, high speed steel cutting tools can also be used. Machinability characteristics are similar to other austenitic stainless steels, such as high toughness. Thus, machining requires rigid fixturing, low cutting speeds and ample cutting fluids. These fluids can be either water-based or of sulfochlorinated oil. Finish grinding is also recommended when very close tolerances are required.

Welding

Multimet N155 has great welding ability, particularly in conjunction with gas-tungsten-arc (GTA), plasma-arc, and electron-beam welding. Welding is generally carried out on solution heat treated material using metal weld filler. In many instances, appropriate post-weld heat treatment is employed to reduce residual weld shrinkage stresses. Strength and ductility are good in the as-welded condition, but a full post-weld solution heat treatment or lower temperature stress relief (1800F min) is often applied to obtain optimum properties (dimensional stability, fatigue life) in weldments.

Forming

Forming is considered very good for Multimet N155 and should be performed in the solution heat treated condition. This created an optimum condition for cold-forming operations because it provides minimum hardness and maximum ductility. When cold-formed, Multimet can be manipulated by most of the common forming methods including drawing, rolling, bending, spinning, drop hammering, punching and shearing. Due to the toughness and work hardenability of the alloy, relatively high energy levels and frequent intermediate solution treatments may be required during severe cold forming operations. Generally, after final cold working, parts should be solution treated to restore the optimum combination of mechanical properties and corrosion resistance.

Corrosion Resistance

Multimet N155 possesses very good resistance to corrosion and oxidation. Oxidation resistance is usable up to 1800F.

Heat Treatment

Multimet N155 wrought products are supplied by the mills in the solution heat treated condition, which provides the optimum combination of mechanical properties and corrosion resistance for practically all applications. The heat treatment for Multimet N155 consists of exposure to heat at 2,150F followed by rapid cooling. The hold time at 2,150F varies with the section size of the product, size of load and furnace characteristics, however, a rule of thumb that provides acceptable results for the product being treated is to hold for 1 hour per inch of thickness. The cooling rate from 2,150F to 1,000F or below should be rapid enough to prevent carbide precipitation, which decreases corrosion resistance and toughness for sheet products. Rapid air cooling is usually adequate for this type of cooling. However, oil or water quenching is frequently necessary for heavier sections.

Forging

Multimet N155 forging should be carried out in the temperature range of 2150 to 1750F with relatively moderate reductions per pass and frequent re-heating.

Property	Value
Tensile Strength	Minimum 100 to 140 KSI (689 to 965 MPa)
Elongation in 2 Inches (50.8 mm) or 4D	40%