Alloy 625 nickel pipe is made from a nickel-chromium-molybdenum alloy with an addition of niobium. High strength and toughness from cryogenic temperatures to 1800°F. Good oxidation resistance, exceptional fatigue strength, and good resistance to many corrosives.

Typical applications include chemical processing, aerospace and marine engineering, pollution control equipment, and nuclear reactors.

GRADE

INCONEL 625 CHEMICAL COMPOSITION

ALLOYING ELEMENTS

The addition of Molybdenum (“Moly”) increases the strength of the steel and its elastic limit, enhance the steel resistance to wear, its impact qualities, and the hardenability. It also improves the resistance to softening, makes chromium steel less prone to embrittlement and prevents pitting.

Chromium, a key element also for stainless steel alloys, prevents steel oxidation at elevated temperatures and increases the resistance of steel to corrosion. It enhances the tensile, yield, and hardness properties of low-alloy pipes at room temperatures.
Other alloying elements, present in various degrees in pipes of all grades are:

• Aluminum: decreases oxygen from steelmaking

• Boron: used to produce fine grain size and enhance steel hardness

• Cobalt: used to enhance the steel’s heat and wear-resistance

• Manganese: gives better steel hardenability

• Nickel: Enhances toughness, hardenability and impact strength at low temperatures

• Silicon: decreases oxygen, enhances hardenability and toughness

• Titanium: prevents precipitation of chromium carbide

• Tungsten: refines steel grain size and enhance the steel hardness, especially at high temperatures

• Vanadium: gives steel enhanced fatigue resistance

As mentioned, low-alloy steels have a total amount of alloying elements below 5%; high alloy steel has a higher percentage of these elements.