Product focus: INCOLOY alloy 925 in the sour gas industry
Corrotherm, as a nickel alloy stockist, only selects the very best materials to add to its product lineup. Each of the Grades we offer have been proven to excel in many applications across key industries, including oil and gas, aerospace and chemical processing.
Alongside the technically advanced INCONEL range of nickel alloys, lie our INCOLOY alloys. These materials are just as effective, but contain less nickel than INCONEL products. Iron is added into the nickel-chromium mix to produce an economical range that still offers exceptional performance in high-temperature and corrosive environments.
One of the standout nickel alloys in the INCOLOY range is INCOLOY alloy 925, an age-hardenable material that offers very high strength. This strength is well retained even at elevated temperatures up to 650°C. The precipitation-hardening heat treatment applied to this alloy increases both the hardness and strength inherent to the material.
Controlled composition
The composition of this technically superior nickel alloy has been carefully developed. The controlled amounts of each individual element help to enhance the properties of the alloy as a whole. The base of the alloy is a blend of nickel, iron and chromium, but it has some key additions: molybdenum, copper, titanium and aluminium.
The nickel content is high enough that the alloy is resistant against chloride-ion stress-corrosion cracking. It also, in conjunction with the molybdenum and copper, provides resistance to reducing media. The chromium imparts resistance to oxidising media, which means this alloy is good for multi-acid environments.
Molybdenum is a popular addition to nickel alloys, as it adds strength as well as resistance to pitting and crevice corrosion. Titanium and aluminum are added in small, but carefully controlled, amounts to cause a strengthening reaction during heat treatment.
Together, all of these elements combine to create a superalloy that offers both excellent corrosion resistance and high strength.
Applications
There are many industries where a nickel alloy of this calibre is required. It is widely employed in the extraction of sour gas. Material selection for the sour gas and oil industry is incredibly complex and there are a lot of factors to take into consideration. Sour gas is difficult to work with and highly corrosive. INCOLOY alloy 925’s good resistance to sulphide stress cracking and stress-corrosion cracking in crude oil and sour environments, makes it a good choice for many down-hole and surface gas-well components. This includes tubular products, valves, hangers, landing nipples, tool joints and packers.
While it is in the sour gas industry that this alloy shines, it does have other uses. It is useful for fasteners, marine and pump shafting, and high-strength piping systems.
