At ChemiPetro, we have high performance pipe flanges in a range of superior alloys such as ferrite-molybdenum and super duplex, specially manufactured for use in the gas, oil and petrochemical industries. To understand why pipe fittings made from these alloys are superior to standard stainless steel, you must first understand what stainless steel is.

Basic stainless steel is itself a ferrite (iron) and chromium alloy, containing a minimum of 10% chromium which makes it resistant to corrosion and oxidation. If this percentage is increased, or other materials introduced (for example nickel or carbon) the physical characteristics of the alloy will be altered.

It is important this is taken into account when choosing products for industrial use. For this reason, stainless steel pipe flanges and other fittings are graded according to the mineral composition of the alloy (i.e. its crystalline structure) Set within narrow, clearly defined limits, this ensures the appropriate product is chosen for each application, and sets quality control standards.

The most common stainless steels are the austenitic or 300 series (also classified under the UNS system). These ferrite-chromium-nickel alloys make up over 70% of stainless steel products made. The most common austenitic grade is type 304 stainless steel (UNS 30400). This is not widely used in submerged or highly corrosive environments, as it has a higher risk of weld decay than, for example, type 321 – which has added titanium to reduce the risk.

Type 316 has added molybdenum for greater corrosion resistance. It is used in undersea pipelines and volatile chemical plants. Type 347 is made with added niobium, which desensitises pipelines during welding.

We at ChemiPetro manufacture a large range of pipe fittings in grades from 304 to 347H, to cover every industrial application.

Although 304 chromium nickel, or austenitic, stainless steel pipe fittings are fine for low-spec applications, most high pressure and volatile chemical systems require a stronger, more resistant alloy.

At ChemiPetro we make alloy pipe flanges and fittings in titanium, molybdenum, duplex, super duplex and stainless steel. Each is graded according to the crystalline structure of the alloy, i.e. the percentage of other materials incorporated into the ferrite matrix.

Alloys are graded by the SAE or UNS system. The SAE 300 series (UNS ‘S’ series) covers all nickel-chromium steel alloys. At ChemiPetro, we have a large range of pipe fittings in SAE 304 grade – the most common austenitic alloy produced.

The SAE 400/500 series covers Molybdenum steels, which are also classified under UNS S and N ratings. Titanium is one of a number of so-called exotic alloys, which does not have an SAE rating but is listed under UNS R ratings.

Where pipe flanges are used in corrosive environments or sea water, super austenitic alloys are used. Also called Moly 6 alloys (to differentiate from the 400 series molybdenum alloys) these come under SAE 600 – 665 categorisation. They offer great resistance to pitting and corrosion, due to their high molybdenum content (6% or higher) and addition of nitrogen during a secondary precipitation process. Additionally, higher nickel content provides great protection against cracking due to stress corrosion.

At ChemiPetro Ltd, we have high resistance pipe fittings in 4 grades of Moly 6 alloy. These are cheaper than titanium alloy pipe flanges, and offer tremendous longevity and protection in undersea pipelines, concentrated chemical plants and oil distillation columns.

At ChemiPetro, we provide pipe fittings for a wide range of industrial uses. Our clients require specific qualities: high strength combined with resistance to corrosion and other stresses.

Grade 304 stainless steel is fine for small plant non-hazardous use. However, the moment you introduce high pressures, caustic chemicals, high temperatures or a marine environment, pipe flanges need to be made from something a bit tougher.

We provide 316, 317, 321 and 347 pipe fittings in both standard and “L” forms. 316 and 317 have added molybdenum for increased resistance to chloride corrosion. In addition, 317 has increased nickel and chromium, making it strong and highly corrosion resistant. It is used in underwater pipelines and pulp bleaching plants.

“L” specifies ultra-low carbon content. Carbon desensitises hot welding joints by forming chromium carbide, which then precipitates out, removing the anti-corrosion properties. This means welded pipe flanges can potentially fail at their most critical point. This is a serious problem in marine pipelines, where hot welding is commonly used. Low carbon steels help prevent this, while still keeping costs low.

321 and 347 alloys have added titanium to further decrease weld decay and sensitization, 347 being further improved with niobium. Both are superior to 316/317 grades, but less costly than duplex, moly and pure titanium alloys.

Ferrite alloys have high corrosion resistance but low strength, so they are combined 50/50 with austenite to create our superior duplex and super duplex pipe flanges, which offer superb durability and resistance under all conditions.

Our Moly 6 alloys, similarly, combine the low carbon attributes of ferrite with the anti-corrosive qualities of molybdenum, to produce top quality pipeline flanges.  Our very top end pipe fittings are those composed of titanium, rather than steel.

At Chemipetro Ltd we have a full range of specialised pipe fittings for use in the most extreme environments.

To prevent corrosion and increase strength, steel is protected in two ways – by galvanisation or by making it into an alloy. Galvanised steel is only coated, whereas alloys are actually combinations of steel and another material, such as carbon, chromium, molybdenum or titanium.

Some metal alloys are further modified, creating ’super’ steel alloys, such as super duplex. Although these are superior in use, the cost of the rare metals used does make them more expensive. To be cost effective, an industry has to balance cost against safety, effectiveness and longevity.

Stainless steel pipe fittings are made from a steel-chromium alloy. They are the cheapest kind, and are fine for certain small plant and low-pressure applications. We at ChemiPetro have a range of popular pipe flanges and fittings in plain stainless steel.

Carbon steel is extremely malleable, and can be used to form small precision components such as narrow bore pipe flanges. By tempering and hardening the steel in different ways, its mechanical properties can be altered. Thus you can custom-design pipe flanges to alter ductility; impact resistance; yield strength, hardness and electrical and thermal conductivity.

Carbon steel is used mainly in the construction and petrol refining industries, although it’s also used in oil, water and natural gas systems. Carbon steel is popularly used where butt-welding – i.e. a permanent and welded construction – is required.

Recent years has seen an influx of new alloys such as titanium-steel, molybdenum-steel and duplex.  These offer unique benefits to the gas, oil and petrochemical industries, which is why so many pipe fittings are composed of these materials. At ChemiPetro we have a wide range of titanium, super austenitic moly and duplex pipe fittings to buyas well as accessories like tie rods.

The word steel covers a whole lot of sub-types: stainless, galvanised and duplex steel are just some of those used for industrial applications.

In this article, we will give you some insight into how steel is made, and why steel alloys, rather than galvanised steel products, are sold by petrochemical and gas suppliers like us at ChemiPetro.

Steel pipe fittings have been around for years due to their strength, durability and heat resistant qualities. The high level of precision that can be achieved when tooling stainless steel makes it ideal for making pipes and pipe fittings, for both household and industry.

Steel pipes are widely used for carrying flammable gases, oil, petrol, chemicals and water for sprinkler systems. Due to steel’s ability to corrode, it is usually combined with other metals and minerals to reduce this.

The cheapest way to improve steel is by chemically coating it, in a process called galvanisation. Zinc galvanised steel is the best known example of this. It is cheap and widely used in water supply lines. However, once the galvanised coating wears off, the steel is weak and quickly corrodes.

For this reason, steel alloys are used for gas pipelines and other industrial specifications. Alloys are created by physically combining the steel with other materials such as carbon, molybdenum or nickel. This reduces corrosion and can also increase strength.

At ChemiPetro, we have pipe fittings in a range of high-spec steel alloys, designed specifically for use in the gas, oil and petrochemical industries. We also supply weld neck flanges for industry use and couplings, amongst other pressure fittings.