Have You Discovered the Allure of Monel 400?

┃ Overview

UNS N04400 (also known as Alloy 400, W.Nr. 2.4360, or Monel® 400) is a single-phase, solid-solution alloy that achieves hardening primarily through cold working rather than heat treatment. It exhibits high strength and toughness across a broad temperature range and demonstrates exceptional resistance to various corrosive environments. Monel 400 retains excellent mechanical properties even at subzero temperatures, with strength and hardness increasing while maintaining ductility and impact resistance. Unlike many ferrous materials, it does not undergo a ductile-to-brittle transition even when exposed to the extremely low temperatures of liquid hydrogen.

┃ Application

Marine Applications: Seawater valves, pump shafts, propeller shafts, fasteners, and other components

Chemical Processing: Pumps, valves, heat exchangers, and reactor vessels

Oil and Gas Industry: Wellhead components, valves, pump shafts, and tubing

Aerospace Industry: Landing gear, fasteners, exhaust systems, and engine components

Electrical and Electronic Components: Electrical connectors, switchgear components, terminals, and in the production of electronic devices

Food Processing: Food handling and processing machinery, heat exchangers, and storage tanks

Seawater Desalination: Pumps, valves, heat exchangers, and tubing

┃ Chemical Composition (%)

Material	Ni	C	Mn	Fe	S	Si	Cu
N04400	63.0 min	0.30 max	2.00 max	2.50 max	0.024 max	0.50 max	28.0-34.0

┃ Mechanical Property

Material	Tensile strength	Yield strength 0,2	Elongation	Hardness HB30
N04400	517-655N/mm²	172-345N/mm²	35-60%	110-215HB

┃Corrosion Resistance

Monel 400 demonstrates resistance to corrosion from numerous reducing agents and provides outstanding resistance to hydrofluoric acid in all concentrations up to its boiling point. This wide-ranging resistance makes Alloy 400 suitable for use in diverse environments, and it is considered one of the most corrosion-resistant engineering alloys available. For instance, in typical fresh and industrial water conditions, Monel 400 can effectively withstand stress corrosion cracking and pitting.

┃Heat Treatment

Both cold-worked and hot-worked Monel 400 require heat treatment to achieve the optimal balance of strength and ductility while minimizing distortion during subsequent machining processes. Heating the material for 1 to 2 hours at temperatures ranging from 1000°F to 1050°F helps relieve strains in both hot and cold-worked products.

┃ Heating and Pickling

Heating is a commonly employed process in treating Monel 400 to reach specific temperature ranges for subsequent procedures such as welding, hot forming, or stress relieving. This helps enhance material ductility, reduce residual stresses, and facilitate further fabrication. When heated and cooled in a reducing atmosphere or quenched in an alcohol-water solution, Monel 400 maintains a bright appearance without discoloration. However, if allowed to cool in air after heating, the alloy will form an adherent oxide film.

Pickling, a chemical process often conducted post-welding, hot forming, or when the material's surface is contaminated, aims to eliminate surface contaminants, scale, and oxide layers from Monel 400, resulting in bright, clean surfaces. This process involves immersing the material in an acid solution to dissolve the unwanted layers. Commonly used acids include a mixture of nitric and hydrofluoric acids or a mixture of nitric and hydrochloric acids. The immersion time varies based on the severity of surface contaminants and the desired level of cleaning.

┃ Hot and Cold Forming

Monel 400 exhibits softer resistance to hot deformation compared to many steels, allowing it to be hot-formed into nearly any shape. The recommended hot-forming temperature range for Alloy 400 is between 1200°F and 2150°F, with a strict upper limit of 2150°F to avoid detrimental effects. Prolonged soaking at hot-working temperatures should be avoided as it can be detrimental. In case of a processing delay, the furnace temperature should be reduced to 1900°F until operations resume.

For heavy reductions, the recommended metal temperature ranges from 1700°F to 2150°F, while lighter reductions can be taken down to 1200°F. Working at lower temperatures yields higher mechanical properties and a smaller grain size.

Monel 400 is also a ductile alloy suitable for cold forming, enabling the creation of various shapes and components without the need for high temperatures. Cold forming processes are typically employed when intricate shapes or fine details are required.

┃Machining

Monel 400 can be machined at satisfactory rates using the machine tools commonly employed in the industry. For optimal machinability and a smooth finish, it is recommended to use relieved material.

┃Welding

Monel 400 can be easily joined using conventional processes and procedures. Most conventional welding processes are suitable for joining alloy 400 to itself or to dissimilar alloys. The selection of welding products depends on the materials being joined and the environmental conditions they will encounter. For certain applications, Nickel Welding Electrode 141, INCO-WELD A Welding Electrode, or INCONEL Welding Electrode 112 may be preferred.

┃ Product Forms

Ø Bar & Rod

Ø Plate & Sheet

Ø Coil & Strip

Ø Pipe & Tube

Ø Fitting: Flange, Tee, Elbow, Reducer etc.

Ø Forging: Ring, Shaft, Circle, Block etc.

┃ Note

Ronsco is a supplier with more than 27 years of experience in the special metal field, we always adheres to the business phiosophy of "customer-centered", tries its best to meet the requirements of customers and pursues win-win cooperation with customers. Are you looking for special metal products one-stop supplier! Contact Us Now! Email: marketing@ronsteel.com