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Types of steel every portable machine tool operator should know about


The environment and conditions that oil and gas pipes, fittings and flanges are exposed to are diverse and extreme. The varying chemical composition of the gases and liquids, the extreme temperatures and physical demands mean that no single material is ideal for all purposes.

Read on to find out about the commonest types of steel used in the oil and gas industry and what they are used for.

To meet the varying demands of the oil & gas industry, the properties of steel can be altered dramatically by the addition of different proportions of materials such as Chromium, Carbon, Manganese, Nickel, Molybdenum, Titanium, Silicon, Phosphorus and Sulphur.

Hardness, corrosion, oxidation, strength and the metal’s ability to weld area all affected in varying degrees by adding the above materials.

Mirage customers will be aware of the high-performance machines we manufacture to machine these ‘super alloys’, so being aware of their different grades and applications in the oil and gas industry will keep you in the know for your future machining projects.


The ‘standard’ grade of stainless steel, as used for kitchen appliances is also utilised in the oil and gas industry. Adding at least 10.5% chromium creates a “passive layer” to prevent against corrosion. Nickel and Molybdenum may also be added to further enhance corrosion protection.

Oil & Gas Applications For Stainless Steel

  • Flowlines
  • Structural Components
  • Umbilicals
  • Heat Exchangers
  • Process Equipment


Duplex stainless steel is very strong, with high corrosion resistance and stress corrosion cracking properties. Compared to other alloys with corrosion resistance properties, Duplex alloys use less Nickel and Molybdenum, making them cost-effective alternatives that are less prone to price fluctuations.

Oil & Gas Applications For Duplex Stainless Steel

  • Oil Country Tubular Goods (OCTG).
  • Storage Tanks & Pressure Vessels
  • Petrochemicals


Carbon steel is made from Iron Steel with less than 2 % of carbon added, plus small amounts of Silicon, Manganese, Phosphorus and Sulphur. Grades available include low, medium and high.

Carbon Steel is very strong, with high resistance to wear and is one of the most produced materials of all steel types. Drawbacks include difficulties welding, machining and susceptibility to corrosion (however, additives can be added to help control this).

Oil & Gas Applications for Carbon Steel

  • Oil Country Tubular Goods (OCTG)
  • Flow lines
  • Structural Components
  • Platforms & Jackets
  • Pipelines


This material is used when applying forging techniques to reshape the metal. Normally this is for components where steel strength heaviness is needed.

Oil & Gas Applications for Forged Steel

  • Wellheads & Christmas Trees
  • Subsea Equipment
  • Valves & Fittings


Also known as special bar quality (SBQ) steel, this is commonly used in moving parts and those where stress resistance and a fine surface finish is required. One of the  key factors determining the performance of the material is its purity, the few impurities the more ‘special’ the grade is.

Oil & Gas Applications for Engineered/SBQ Steel

  • Completion Equipment
  • Shafts, Bearings
  • Drill Bits


Adding Nickel to steel increases the resistance to corrosion. Unfortunately, it is a rare and declining resource.

Oil & Gas Applications For Nickel

  • Wellheads, Christmas Trees
  • Subsea Equipment
  • Valves & Fittings
  • Oil Country Tubular Goods (OCTG)
  • Down-hole Equipment & Tools
  • Completion Equipment
  • LNG & Natural Gas Processing Plants


This is another declining material and is used as an additive to produce stainless steel and corrosion resistant alloys. Grades of chromium based steel products range from Cr13 to Cr35.

Oil & Gas Applications For Chromium Steel

  • Wellheads, Christmas Trees
  • Valves & Fittings
  • Oil Country Tubular Goods (OCTG)
  • Down-hole Equipment & Tools
  • Completion Equipment
  • LNG & Natural Gas Processing Plants


This material provides 3 benefits when added to steel, not only does it increase strength and improve corrosion resistance, because of its high meltng point it also ensures the metal can be used in extremely high temperature environments.

Oil & Gas Applications for Steel With Molybdenum

  • OCTG
  • Down-hole tools
  • Drill bits
  • Used as catalyst in petrochemicals industry


Inconel alloy is a trademarked corrosion resistant ‘super alloy’. These alloys are very hard to machine and weld and contain up to 70% Nickel and up to 70% Chromium,  making them suitable for use in high temperature, corrosion and pitting environments, acid applications, exposure to high mechanical stress and sea water. Common grades used in the Oil & Gas industry are 718, 628, 625,825, and 945. For wellhead applications, Inconel 718 (solid) Inconel 625 (as cladding) are commonly used. Inconel 718 is also used for completion equipment in sour applications.

Oil & Gas Applications For Inconel

  • Chemical Processing Equipment
  • Components of gas turbines,
  • Valves
  • Completion Equipment in sour applications
  • Drilling Tools
  • MWD / LWD components
  • Flare booms
  • Wellhead Components (hangers)


Incoloy alloy is another trademarked alloy that is corrosion resistant but a more cost-effective alternative to Inconel, as it has higher composition of ferrous (iron). Incoloy alloys are best suited for sour gas, high chloride, process piping and aqueous environments, such as seawater and brine.

Incoloy 945 and 945X as the most recently developed alloys and are known to be one of the best corrosion resistance alloys available and used in Oil & Gas Industry only.

Oil & Gas Applications For Incoloy

  • Completion Equipment
  • Packers
  • Drilling Tools
  • MWD / LWD components
  • Liquid / fluids separators


Monel is another trademarked corrosion resistant super alloy. It is a nickel and copper based alloy (60% and 30% respectively) and used in many applications. Common grades in the Oil & Gas Industry are K500 and 400. Monel K500 is used in completion equipment with high corrosion resistance and higher strength requirements

Oil & Gas Applications For Monel

  • Pumps & Valves
  • Heat Exchangers
  • Electrical Components
  • Down-hole Equipment & tools


Hastelloy is a corrosion / oxidation and erosion resistant nickel-molybdenum alloy with high mechanical strength, especially when at high temperatures. Petrochemical plants are a major user of Hastelloy.

Oil & Gas Applications for Hastelloy

  • Pumps & Valves
  • Heat Exchangers
  • Pressure Vessels


Although its not a type of steel, we wanted to give Titanium a mention because of the benefits such as it’s very light, but also very strong and has a with corrosion-resistant qualities.

Oil & Gas Applications For Titanium

  • Where weight reduction is needed
  • Pumps
  • Heat Exchangers
  • Risers
  • Subsea Equipment

 If you need portable equipment to machine any of the above, get in touch with your regional contact using our enquiry form, or by using our online chat service available on our main website.

Download the Complete Guide to Managing Flanges

Sources: Guide to Metals, Steel and Alloys in Oil & Gas Industry - Daleel Oil & Gas Supply Chain Portal  http://www.scmdaleel.com/article/guide-to-metals-steel-and-alloys-in-oil-amp-gas-industry/216

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