Inconel 625 

Inconel 625  Of Specifications

• Inconel 625
• JIS NCF 625
• Alloy 625
• AFNOR NC22DNB4M
• UNS N06625 W. Nr./EN 2.4856
• DIN 2.4856
• EN NiCr22Mo9Nb BS NA 21
• GOST ХН75МБТЮ
• OR ЭИ602

Alloy 625 undergoes some hardening when exposed to intermediate temperatures. During 2000 hours, samples of annealed rod were exposed to 1200°, 1400°, and 1600°F. In order to determine dimensional stability, samples were exposed at 1200° to 1400°F for 2000 hours

Inconel 625 Thermal Conductivit

• CAPACITY – The machine should be rigid and overpowered to the maximum extent possible.
• RIGIDITY – Work piece and tool should be held rigidly. Overhangs on tools should be minimized.
• TOOL SHARPNESS – Keep tools sharp at all times. Rather than only sharpening tools when necessary, change them regularly. Tools with a wear land of 0.015 inches are considered dull
• TOOLS – For most machining operations, use positive rake angle tools. Intermittent cuts and heavy stock removal can both benefit from negative rake angle tools. Most applications require carbide-tipped tools. Intermittent cuts often require high speed tools, which have lower production rate.
• POSITIVE CUTS – Maintain a positive cutting action by using heavy, constant feeds. When feed slows and the tool dwells, work hardening occurs, tool life deteriorates, and close tolerances are impossible.
• LUBRICATION – When using carbide tooling, soluble oils are recommended.

A wide variety of severe corrosive environments can be tolerated by INCONEL alloy 625 due to its high alloy content. There is almost no attack in mild environments such as the atmosphere, fresh and seawater, neutral salts, and alkaline media. In more severe corrosive environments, nickel and chromium provide resistance to oxidizing chemicals, while nickel and molybdenum provide resistance to nonoxidizing environments. In addition to its high molybdenum content, niobium stabilizes the alloy against sensitization during welding, thus preventing subsequent intergranular cracking. Furthermore, the high nickel content prevents chloride ion stress corrosion cracking.

Aqueous Corrosion

Because INCONEL alloy 625 contains a high alloy content, it can endure severe corrosive conditions. There is almost no attack in mild environments such as the atmosphere, fresh and sea water, neutral salts, and alkaline media. Nickel and chromium provide resistance to oxidizing chemicals in more severe corrosive environments, while nickel and molybdenum provide resistance to nonoxidizing environments. Niobium helps stabilize the alloy against sensitization during welding, preventing subsequent intergranular cracking due to its high molybdenum content. The high nickel content also prevents chloride ion stress corrosion cracking. The combination of these characteristics makes INCONEL alloy 625 suitable for a wide range of corrosive environments. Among other things, it is recommended for construction of tanks for storage of chemical wastes, including hydrochloric and nitric acids – chemicals with opposite corrosion problems. Normally, materials that resist either of these acids are severely attacked by the other.

High-Temperature Oxidation  

The INCONEL alloy 625 is resistant to oxidation and scaling at high temperatures. Figure 15 compares its performance in a severe test with that of other materials. Periodic weight-loss measurements indicate the alloy’s ability to retain its protective oxide coating under extreme cycling conditions. Scaling resistance becomes significant at 1800°F.

• Sheet
• Plate
• Bar
• Pipe & Tube (welded & seamless)
• Wire

Fabrication with Inconel 625
The alloy 625 has excellent forming and welding characteristics. When the temperature is maintained between 1800 and 2150° F, it can be forged or hot worked. In order to control grain size, finish hot working should be performed at lower temperatures. Alloy 625 is also readily formed by cold working due to its good ductility. However, the alloy does work-harden rapidly, so intermediate annealing treatments may be required for complex component forming operations.

 For the best balance of properties, all hot or cold worked parts should be annealed and rapidly cooled. Both manual and automatic welding methods can be used to weld this nickel alloy, including gas tungsten arc, gas metal arc, electron beam, and resistance welding. The material exhibits good restraint welding properties

Weldability of Inconel 625

Because Inconel 625 is ductile and strong at low temperatures, it has high strength, fatigue and thermal-fatigue strengths, improved oxidation resistance, and excellent weldability and brazeability, so it is used in a variety of industries. Due to its high tensile strength and weldability, Inconel 625 tubing is popular in the aerospace industry.

Using tungsten electrodes or consumable electrodes, gas-shielded welding can be performed. It is not necessary to heat treat the weld after welding to maintain corrosion resistance. The mechanical properties of heavy restrained sections follow the same trend as those of base metals.

In the 1960s, Inconel 625 was developed for the sole purpose of manufacturing steam-line piping. As a result of further changes to Inconel 625’s composition, it is even more creep-resistant. There are a variety of industries that use Inconel 625, from chemical processing to marine and nuclear applications to pumps, valves, and other high-pressure equipment. The alloy is also used in the following areas:

• • Aircraft ducting systems
  • Jet engine exhaust systems
  • Engine thrust-reverser systems
  • Specialized seawater equipment
  • Chemical process equipment

Nickel-chromium alloy Inconel Alloy 625 is non-magnetic, corrosion and oxidation resistant. The combination of molybdenum and niobium on the nickel chromium base of Inconel 625 gives it its high strength. High-temperature effects such as oxidation and carburization are not a problem for Inconel 625 when exposed to unusually severe corrosive environments. The solid solution effects of columbium and molybdenum in a nickel-chromium matrix give this material its outstanding strength and toughness in temperature ranges from cryogenic temperatures to 2000° F (1093° C). For sea-water applications, nickel chromium alloy 625 is an excellent choice because of its excellent resistance to pitting and crevice corrosion, high corrosion-fatigue strength and high tensile strength. Both aerospace and marine applications use Inconel. Among its applications are springs, seals, bellows for submerged controls, electrical cable connectors, fasteners, flexure devices, and oceanographic instrument components.

CHARACTERISTICS OF INCONEL 625

• High strength and mechanical properties at both cryogenic and high temperatures.
• High oxidation resistance at temperatures up to 1050°C.
• High tensile, creep, and rupture strength.
• Good resistance to oxidizing and reducing acids such as nitric, sulfuric, hydrochloric and phosphoric acid.
• Virtually immune to chloride ion stress-corrosion cracking and pitting, making it ideal for marine applications.
• Excellent weldabilty

INCONEL 625

Trade names include Inconel 625®, Chronin® 625, Altemp® 625, Haynes® 625, Nickelvac® 625, Nicrofer® 6020, UNS N06625.

Nickel-based alloy Inconel 625 is nonmagnetic, corrosion- and oxidation-resistant, and also known as Incoloy 625. As a result of the solid solution effect of columbium and molybdenum in a nickel-chromium matrix, alloy 625 exhibits high strength and toughness in the cryogenic to 2000°F (1093°C) temperature range. The alloy 625 exhibits excellent fatigue strength and stress-corrosion cracking resistance to chloride ions.

A variant of INCONEL® 625 is INCONEL® 625 LCF. Low Cycle Fatigue is also known as LCF. Thus, the alloy has improved cycle fatigue properties and thermal fatigue resistance. The alloy is similar to INCONEL® 625 in terms of chemical composition and other mechanical properties. Bellows, aircraft exhausts, and expansion joints are among the uses of the alloy.

Alloy 625 (UNS N06625) chemical analysis

Inconel 625®, Chronin® 625, Altemp® 625, Haynes® 625, Nickelvac® 625, Nicrofer® 6020.