September 24th, 2009
While literally hundreds of specialised pipe fittings are available, there are others that are commonly used for piping systems.
Elbow pipe fittings are amongst the most common worldwide. This fitting is designed to change the direction of a flow running through a pipe, usually at a 90 degree or 45 degree angle. 45 & 90 degree elbows are installed between two lengths of pipe. The ends of the fitting can be either butt welded, threaded or socketed. If each end of the fitting is of a differing size it is called a reducer elbow.
The Tee pipe fitting is used in applications that require a flow to be combined or split. The most common type are those that have the same inlet and outlet size. However as per elbow fittings they can also be reducing tees. Tee pipe fittings make up an integral part of level water cooling solutions. This type of fitting is one component of a T Line.
The principle behind pipe fittings is to connect sections of straight piping. They can be used to adapt the piping to different sizes or shapes and are necessary to regulate the flow through the pipe.
Steel piping or black iron was once the most common material used in piping that carried water or flammable gases. However this steel had a tendency to rust and so fell out of favour. While steel of this type is no longer used stainless steel fittings are very much in favour.
Stainless steel provides good corrosion resistance features, and thanks to its demand around the world is an affordable option for industries or applications that demand high levels of rust or corrosion free properties.
As a leading UK manufacturer and supplier of pipe fittings, we at Chemipetro should be any organisation’s first port of call for high quality common pipe fittings.
Tags: 45 & 90 degree elbows, high quality pipe fittings, Pipe Fittings, reducing tees
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September 23rd, 2009
Duplex stainless steel was first created in order to address corrosion problems stemming from chloride bearing cooling waters or other chemical process fluids.
Duplex stainless steel is a family of grades which are ranged in accordance to their corrosion performance, as well as their content of alloy; Duplex’s alloy content being almost equal proportions of ferrite and austenite.
Super Duplex was a term phrased in order to indicate its highly alloyed composition of which provides a pitting resistance of >40. The chemical composition is based on Cr% + 3.3Mo% + 16N%.
Super Duplex contains very high levels of chromium which provides above average resistance to acids, caustic solutions and acid chlorides. It also provides high levels of corrosion resistance to any environment which uses chemicals or petrochemical solutions. It is fast replacing 300 series stainless steel or high nickel super-austenitic steels.
Based on a chemical composition which has high contents of nickel, chromium and molybdenum, Super Duplex improves intergranular and pitting corrosion resistance. With the addition of nitrogen to promote structural hardening it not only raises yield strength but also strength values without impairing its toughness.
The Various Alloys
Super Duplex stainless steel resides in the group of Duplex stainless steel. It is graded for its corrosion performance and for its content of alloy. Duplex can be divided into four groups:
1. Super Duplex, which contains 25-26Cr and increased Mo and N. This grade is comparable to 25 Cr and 2507
2. Lean Duplex stainless steel such a 2304 which contains no added Mo
3. 2205, which is a grade considered the work horse as it accounts for over 80% duplex use
4. 25 Cr duplex.
All of these materials are available from us here at Chemipetro.
Tags: Duplex, duplex alloys, duplex stainless steel, Super Duplex
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September 22nd, 2009
Super Duplex stainless steel owes its existence to Duplex stainless steel, a material developed in Sweden around 70 years ago. Its composition consisted of a microstructure that contained almost equal parts of ferrite and austenite, and became one more family of grades that ranged in its corrosion performance.
Even the term ‘Super Duplex’ denotes that it is a highly alloyed and super performing Duplex stainless steel material, with superior resistance to pitting and corrosion.
Benefits of Super Duplex:
Super Duplex is highly resistant to a variety of potential corrosion types, including chloride stress, suphide stress and cracking, or fatigue. This extremely strong material has a low coefficient expansion and high thermal conductivity, and its levels of resistance to corrosion make it an ideal material to use for a variety of purposes. Super Duplex provides good workability properties and weldability, and has high energy absorption.
Applications suited to Super Duplex
Super Duplex stainless steel is suited to a wide variety of applications, such as:
• On use on tubes or pipes used for the production of or handling of gas and oil
• Heat exchangers and piping used in desalination plants
• In the used of mechanical or structural components
• Piping or pipe fittings used in process industries that contain chlorides
• In industrial systems where high corrosion fatigue is needed including rotors, fans, shafts or press rolls
• On Cargo tanks, sea going vessels or welding consumables used on chemical tankers
• Any application that calls for a high strength solution.
Here at Chemipetro, a leading supplier and manufacturer of flanges and pipe fittings, we supply high quality Super Duplex stainless steel materials to suit an array of purposes.
Tags: Duplex, Pipe Fittings, Super Duplex, super duplex stainless steel
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September 17th, 2009
The two phase microstructure led to the name Duplex. The microstructure consists of grains of ferritic and austenitic stainless steels. When Duplex stainless steel melts it hardens from this liquid phase into a completely ferritic structure. As it cools to room temperature approximately half of these ferritic grains change into austenitic grains. The result is that Duplex stainless steel contains about half of each material, ferrite and austenite.
This Duplex structure gives this particular family of stainless steel its much applauded properties. For one it provides about twice the strength of regular ferritic or austenitic stainless steels. Duplex stainless steels also provide much higher levels of toughness and ductility over ferritic grades. They don’t, however, match these superior properties provided in austenitic grades of stainless steel.
Superior Qualities
While all stainless steels offer resistance to corrosion, the levels depend on their individual compositions. If chloride pitting or crevice resistance is required then they must contain in their composition a mixture of chromium, molybdenum and nitrogen. Duplex stainless steel has corrosion resistance levels that are similar to austenitic stainless steels. For instance from types 304 or 316 grades to 6% molybdenum stainless steels.
Duplex grades have excellent resistance to stress corrosion cracking. This is a property that has been inherited from their ferritic makeup. While austenitic stainless steels provide superior corrosion resistance, ferritic stainless steel provides superior stress cracking resistance.
Due to the lower nickel and molybdenum composition, Duplex stainless steels can be lower in cost. Apart from this and due to their yield strength, it is often possible to reduce the thickness. The combination of these two factors offers not only cost savings, but also savings in relation to weight – especially when compared to austenitic stainless steels.
Duplex stainless steel can be found here at Chemipetro, one of the UK’s leading manufacturers of pipe fittings and flanges, for reasonable prices.
Tags: austenitic stainless steels, Duplex, duplex alloys, duplex stainless steel, ferritic stainless steel
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September 15th, 2009
The principle behind flanges is that mechanical force needs to be exerted in order to preload the gasket. The mechanical force is usually provided by bolts. The reason for this is that when internal pressure is applied, the flange – in conjunction with a gasket – is able to maintain a seal.
They allow for two pipes to be mechanically connected to one another. They also allow for a pipe to be mechanically connected to a host of other equipment such as a valve or tee fitting. A flange however needs to be first attached or connected to the pipe through either welding or threading. They can be used either internally or externally for strength. Their use allows for the easy assembly or disassembly of pipes.
Flanges are sized according to their nominal bore size, which for most pipes does not represent their actual outside or inside diameters. For instance a pipe with a nominal diameter of say 1 inch is not indicative of the size of the pipe. In this instance the outside diameter would be 1.315 inches. The inside diameter of any pipe is determined by the thickness of its wall. For this reason it is imperative that manufacture of all and any pipe flanges is matched to the piece of the bore size of the matching pipe.
Industry Standards
The manufacture of flanges is subject to various industry standards, all of which are adhered to by us here at Chemipetro; a reputable, leading supplier worldwide of pipe fittings and flanges.
One such standard is the NORSOK standard. This standard is intended to confirm or bear out the fact that a manufacturer has the experience, the qualifications and the necessary equipment and facilities to manufacture according to the acceptable properties of the materials being used. The materials in question are Duplex SS, high alloyed austenitic SS, Nickel based alloys and Titanium and its alloys.
Tags: Duplex, duplex alloys, Flanges, Pipe Flanges
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September 10th, 2009
In order to understand Duplex stainless steel, it is first necessary to understand the alloys which are present in it. These are Ferritic Alloys and Austenitic Alloys.
Austenitic Alloys are produced from a combination of both an iron solution and an alloy which when cooled, change into other mixtures; such as cementite and ferrite. At times – and to some extent – pearlite is also produced from the mixture. This is an alloy that is able to withstand corrosion and due to its cold working, provides far increased strength.
Austenitic alloys consist of two types of series, the first being the 200 series. The 200 series contains nickel, chromium and manganese while the second 300 series contains only chromium and nickel. Austenitic’s mechanical properties can be changed via the use of quenching, tempering or annealing.
Ferritic Alloys belong to the 400 series of stainless steel alloys. It is an alloy that is more popular than iron as it contains the same substances capable of producing cast iron and steel. Each is not hardened even when submitted to heat treatments or other solutions. Ferritic alloy is also resistant to corrosion due to its oxidation properties.
Duplex stainless steel is known for its corrosion resistant properties, which lends itself to both the construction and forming of flanges and pipe fittings.
Duplex stainless steel was introduced to the welding industry in the 90’s. Its primary focus lay in welding but since then its uses have been developed and expanded. Its properties were so well presented that fabricators and engineering specialists immediately saw its potential in construction uses.
Luckily, these materials are now available through us: leading flange supplier Chemipetro.
Tags: Duplex, duplex alloys, duplex stainless steel, Flanges, Pipe Fittings
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September 9th, 2009
The most important aspects of Duplex stainless steel lies in it uses. Fabricators, while not being especially interested in its chemical properties, are interested in its advantages or disadvantages as well as the ease in which it can be fabricated.
Metallurgists on the other hand are interested in it s composition as well as its end usage.
In the fabrication of flanges, Duplex stainless steel offers many advantages. While there exists no all purpose material that can resist corrosion Duplex alloys are in a class that offers superior corrosion resistance.
For instance, in an environment where chlorides are present Duplex alloys give a good performance rating when put against 300 series stainless steel, which gives a poor performance rating.
Where general acids are present Duplex alloys gives a good performance against 300 series stainless steel which again gives a poor performance. Where Hydrofluoric Acid is present the only alloy that gives a better performance than Duplex alloys is either silver or gold.
In the manufacture of high quality flanges, Duplex stainless steel is cheaper than other materials that offer corrosion resistant features. In comparison to 300 series stainless steel Duplex offers a yield strength that is double. This means that in fabrication a thinner material is all that is needed to support an equal load.
It is cheaper to fabricate due to its ease of machining and welding. The ferrite content allows for welding that is less intimidating than high nickel alloys. All that is recommended for welding Duplex alloy is a slight weave bead and a higher heat input.
We at Chemipetro are a leader in the field when it comes to supplying Duplex stainless steel flanges to worlwide industries.
Tags: Duplex, duplex stainless steel, Flanges, Pipe Flanges
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September 8th, 2009
The purpose of a flange is to connect to either two pipes together, a pipe to a valve or tee or to connect a pipe to a choke or any other piece of equipment.
These are the various types of flanges and their uses.
1. Blind Flanges. A blind flange has no bore. It is used in applications to close the ends of piping systems, and this type of flange also allows easy access to the line once it has been sealed. Blind flanges may be machined in order to accommodate a pipe of nominal size which has been reduced. The reduction can take the form of either a thread or a weld.
2. Weld Neck Flanges. This type of flange is drilled to a point where the wall thickness is machined to match the dimensions of the pipe. The lighter the pipe is the larger the bore must be, and visa versa. These flanges can be used for high pressure, cold or hot temperature applications.
3. Slip-On Flanges. A slip-on flange is one that is bored to a slightly larger size than the pipes outer diameter. The pipe then slips into the flange and is then welded inside and out in order to prevent leaks.
4. Orifice Flanges. The function of these flanges is to meter the flow of either gas or liquids in the pipe. Jack screws are needed to spread the flange apart in order to change an orifice plate that is situated between two flanges.
5. Socket Weld Flanges are similar to slip-on flanges. The difference is that a counter bore in required which is slightly bigger than the outer diameter of the pipe which allows the pipe to be inserted.
Here at Chemipetro, each of the aforementioned types of flange are stocked to suit any possible specification.
Tags: Blind flanges, Flanges, slip-on flanges, socket weld flanges, weld neck flanges
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September 3rd, 2009
Super Duplex stainless steel is designed with specific applications in mind. These applications include anything that requires high strength, plus that require above standards of excellence in terms of corrosion resistance. Super Duplex stainless steel lends itself to industries or applications such as sea water cooling plants, ocean vessels, desalination plants or heat exchanger tubes.
Machining, Forming, Welding and Hot Working
Due to Super Duplex stainless steel’s higher yield strength forming pressures, speeds – at least initially – must be higher than what is needed for 300 series stainless steel. All common methods of welding can be employed while hot working is recommended, followed by rapid cooling. Super Duplex stainless steel should also be fully annealed prior to working in order to maximize its properties.
Super Duplex Properties
Super Duplex stainless steel is NORSOK approved and has a pitting resistance equivalent number of 40. Its ability to provide high resistance to corrosion is due to the addition of chromium, molybdenum and nitrogen. Some levels of Super Duplex stainless steel such as F55 / UNS 32760 are too low in nickel and are thus capable of producing a duplex microstructure consisting of ferrite and austenite.
This level of Super Duplex stainless steel can be used in applications such as piping, pumps, chemical tanks, refineries, marine shafts, pressure vessels, flanges, pipe fittings and pipe flanges or heat exchangers where austenitic stainless steel would otherwise corrode.
NORSOK Approved
NORSOK standard is considered critical for the manufacturing or fabrication of components or materials that use induction or cold blending. It is able to establish a set of requirements that can verify a manufacturer has the required competence and experience in the fabrication of materials such as Super Duplex SS, High Alloy Austenitic SS and Nickel based alloys.
As the UK’s premier stockholder, manfucturer and supplier of pipe fittings, flanges and Super Duplex stainless steel, we at Chemipetro should be your first port of call.
Tags: Flanges, Pipe Fittings, Pipe Flanges, Super Duplex
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September 1st, 2009
Although many different flange standards are found worldwide, the principle behind each is to allow the easy inter-changeability and functionality. For this reason, pipe flanges are designed around standard measurements.
These include world standards, such as ASA/ANSI for the USA and BS10 for Britain and Australia. Amongst these standards are manufacturing specifications that stipulate the materials used and their pressure ratings.
BS10 Standards for Pipe Flanges
These standards specify the requirements needed for the manufacture of pipe flanges. The relationship between temperature and pressure according to specific materials is illustrated.
In many cases, BS10 pipe flanges are not interchangeable with international standard flanges. International standards also differ in regard to pressure classes. Each international class will show different pressure ratings. They also show different temperature ratings for different materials. While pressure classes are developed in accordance to their use, they may at times be unique for certain industries or concerns. For instance a contractor or a process plant owner.
Pipe flange faces are manufactured to standard dimensions. They are also manufactured with different faces. While they are typically flat they can also be take be styled as raised, tongue and groove or ring joint.
Their designs differ as well and can take the form of either welding neck pipe flanges, slip-on, boss pipe flanges, lap joint, socket weld, threaded or blind pipe flanges.
ANSI Standards
ANSI designations are designated a number which is proceeded by a ‘#” symbol. This number does not relate to a pipe flanges’ pressure rating or to its weight in pounds; instead, it relates to the class of pipe flange. A pipe flange with a rating of ANSI #300 is rated for a test pressure of 740 psi within a certain range of working temperature.
At Chemipetro, we supply a standard range of high quality pipe flanges for whatever needs you may have.
Tags: blind pipe flanges, Flanges, Pipe Fittings, Pipe Flanges, weld neck flanges
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