Measures to prevent deformation of large flange

Large flange in assembly welding. To avoid in the condition of bearing or bearing welds, try to eliminate the influence of external forces of weld bead and prevent deformation of the flange. Take the following measures:
(1) when conditions permit, the horizontal barrel level in roller frame assembly welding flange. After welding flange in the mouth of the first welding flanges outside the mouth. Welding current and voltage shoulds not be too big, in order to reduce the accumulation of heat.
(2) when necessary, can give the flange stiffened plates equipped with process closed to resist deformation trend. Stiffened plates removed after welding process. And the welding scar left by the bridge polishing.
(3) when the cylinder is in vertical position assembly welding equipment flange, should try to support cylinder, the flange in a suspended state, giving the function of weld bead is not affected by tube weight force.
(4) if necessary, can be used on the bolts in the flange fixed another companion flange, then the normal assembly welding flange. After welding to remove companion flange.
In short, as long as the welding process to take appropriate measures before four, even if again big, again weak flange can also ensure that will not happen deformation during welding.
Source: Yaang Pipe Industry Co., Limited (

What Is Forged Pipe Fittings?

The forged pipe fittings are mean that pipes are through the technology of forging.Commonly the forged pipe fittings includes:socket weld pipe fittings and threaded pipe fittings.

Forged Pipe Fittings Standard:

We supply forged pipe fittings according to GB/T14383,SH3410,ASME B16.11,BS3799 and Custom-made.We supply a variety of forged pipe fittings to satisfy our customers’ specific requirements. Our products are produced strictly according to the required standard.

Forged Pipe Fittings Size:

Yaang supplies forged pipe fittings Dimension DN6-DN100.It has all kinds of size.They are generally small size.We can according to the size of production.In forging the purpose of each size is different.The customer wants to type can be booked.

Forged Pipe Fittings Pressure:

We under the pressure of production in 3000/6000/9000/10000 PSI.The PSI’s English is full of Pounds per square inch,which said the pressure of the forged pipe fittings.

Forged Pipe Fittings Material:

The forged pipe fittings could be Carbon Steel,Stainless Steel,Alloy Steel,20#,A105,20Mn,A350LF2,ASTM A182 F5,F9,F11,F12,F22,F91,F304L,F316L,F321,F347,F51.

Yaang is mainly producing forged pipe fittings and other products in China.We supply a variety of pipe fittings to satisfy our customers’ specific requirements. Welcome to contact us when you have any need about all kinds of forged pipe fittings.

The tolerance of butt welding pipe fitting products

butt welding pipe fitting means the pipe fitting which has the connecting end for butt welding.Commonly the butt welding pipe fitting products includes elbows,tees,reducers, caps,paddles,stub ends,crosses,hot induction bends.The butt welding pipe fitting products are widely used in Industry field,like Oil,Gas & Petrochemical,Energy & Power plant,Chemical industrial,Shipbuilding & Offshore Development.

Our butt welding pipe fittings products commonly according to standard ANSI/ASME B16.9 and ANSI/ASME B16.28,there are other standards about butt welding pipe fittings such as:EN 10253,DIN,JIS,MSS SP-43,MSS SP-75,GOST.We also manufacture the butt welding pipe fittings as per client’s requirements.The butt welding pipe fitting tolerance within the scope of the following:

Butt Welding Pipe Fitting General:

Cross-sectional tolerances for all butt welding pipe fittings (ASME/ANSI B16.9 and B16.28):

Cross-sectional tolerances for all butt welding pipe fittings (ASME/ANSI B16.9 and B16.28)

Alignment tolerances are concerned with the way that the ends of a fitting are cut. Exaggerated distortions are shown for clarity in the diagram below.

Alignment tolerances are concerned with the way that the ends of a fitting are cut

Alignment tolerances (ASME/ANSI B16.9 and B16.28):

Alignment Tolerances(ASME/ANSI B16.9 and B16.28)

Tolerances for Specific Fittings

Dimensional tolerances for elbows and returns (ASME/ANSI B16.9 and B16.28):

Cross Sectional Tolerance For Butt Welding Pipe Fittings

Dimensional tolerances for reducers, caps and stub ends (ASME/ANSI B16.9):

Dimensional Tolerances For Reducers Caps and Stub Ends

Yaang manufacture forged pipe fittings,pipe flanges,steel pipes according to international standards or customer’s requirements.If you have any requirements about the butt welding pipe fittings, welcome to contact us.

Source: Yaang Pipe Industry Co., Limited (

The Application and advantage of butt welding pipe fittings

The application of butt welding pipe fittings:
 butt welding joint steel elbows
The butt welding pipe fitting end is connected to the end of pipes or fittings by butt welding joint, it could be connected to weld neck flange too. The diameter and thickness of the pipes and fittings ends should be in same size and schedule and material. The butt welding joint cound be installed by manual or machine welding and inspected after welding.The following picture is a butt welding joints of  a steel pipe , a steel tee and a weld neck flange in yaang factory for pre-fabrication.
weld flange flange pipe and tee butt welding joint
Butt welding pipe fittings commonly are used for pipe joints which are not changed and assembled. For example,    underground piping systems, long distance pipelines.
hot induction bend butt welded to pipeline underground
The advantage of butt welding pipe fittings:
pipe bevel end for butt welding
Comparing to other type of steel pipe fittings products, butt welding pipe fittings has advantages:
1.Butt welding joint is permanently leakproof and strong.
2.Continuous steel structure of the joints between the pipes and fittings have a good strength in the piping system.
3.The butt welding pipe fittings commonly have a smooth surface and gradual directional changes, it will decrease the pressure losses and turblence of the system, and protect from the corrosion and erosion.
4.The butt welding pipe fittings have a lower cost in bugdet.
5.The butt welding joints have a smaller space in the system.
steel pipe and tee butt weding connection
Yaang can supply the butt welding pipe fittings, forged pipe fitting, steel pipe and flange products as per standard and clients’ requirements.Our butt welding pipe fittings are used in various industry projects because of their advantages. Welcome to contact us ( for further information about butt welding pipe fittings, forged pipe fittings, steel pipe, flange product.
Source: Yaang Pipe Industry Co., Limited (

What is butt welding mean?

What is butt welding mean?

The strategy of butt welding is often a welding joint.When butt welding, material together two parts in a single lines are parallel over the edge.Butt welded joints can be produced with a large continuous or portable welding machine operation.Butt welded joint is surely an economical and reliable technique of joining materials without any additional components.

butt welding plate and pipe
Butt welding process bring metal and plastic.When two plates(or steel sheets) lay side by side and welded together over the line, this can be a typical instance of butt welding joint.
plate with v groove for butt welding
If the thickness from the materials are thin, square and plain materials close to the butt welding joint is alright.In the event the welding material thicker, the extra edge should be beveled to form a single V groove or double V groove, the double V groove is employed for that thickest thickness, it means how the materials are beveled for side.Along with the filler is going to be placed and Welding for side.The double V butt welding is frequently useful for the very thicker and enormous objects.
butt welding end groove for different thickness
In Yaang.Com, a lot of butt welding joints in our products.
1.Our main pipe fittings products are butt welding pipe fittings products, their ends are plain end or bevel end for butt welding connection. 
2.Large size pipe fittings products are produced from steel plate, they are welded in body, not seamless.Those pipe fittings are produced in butt welding method. 

3.The weld neck flange, when a weld neck flange is welded to the pipes, the welding joint is butt welding. 

4.Piping prefabrication, for such fabrication products, when we design it, we perfer to use joints of butt welding method.

Because butt welding joints is very strong and secure for materials.

Source: Yaang Pipe Industry Co., Limited (

pipe bevel end for butt welding

How to choose the type of stainless steel pipe fitting?

Because stainless steel pipe fitting is their condition in a number of different joint made to work, and so has to pick a suitable pipe fitting type, to get the very best usage of join performance. Mainly reflected inside the characteristics of pipe fitting types, namely, the development of the liquid leaving the pipe of the shape as well as its operating performance.

pipe selection factors flow, pressure, liquid angle, coverage, impact, temperature, materials, applications, and the factors in many cases are implicated the other, mutual restraint.

The stainless steel pipe fitting you can pick:

metal grease fitting material should be in line with the chemical properties with the bath to discover:

1, for non-corrosive bath in accordance with the futility of processing, the use of alloy steel pipe fitting

2, to avoid corrosion, stainless steel pipe fitting can be utilized

3, sulfuric acid, hydrochloric acid and also other strong corrosive bath, may be seamless pipe fitting

4, to the phosphate bath pipe materials frequently used acid-resistant stainless steel

5, to stop corrosion from the pipe fitting can even be directly created from metal or nylon production.

Source: Yaang Pipe Industry Co., Limited (

The wall thickness of elbow is beyond the standard

Due to the site of the arrival of the The wall thickness of elbow exceeds bid badly, need to be done according to the actual measurement of pipeline stress calculation, the calculation of wall thickness to exceed bid, pipes, pipe stress on device interface thrust and torque is qualified, and whether to set up reasonable pipe rack. In the pipeline stress calculation procedures, bend the wall thickness of the default for the connection pipe wall thickness, calculating the stress strengthening coefficient of elbow and flexible coefficient. To accounting need to select the wall thickness of the pipe connected to the elbow. By the weight of the elbow to convert in this wall thickness, the bend along the centerline and diameter into a straight pipe (straight pipe length equals the bend axis length), the weight unfolds the straight pipe and elbow weight is consistent, the straight tube wall thickness for the bend in the form of weight reduced wall thickness.
The elbow convert of calculated thickness back to piping stress calculation model, can be bend the impact on the pipeline after the wall thickness of paint.
1. The stress influence of the pipes
The wall thickness of elbow change before and after the pipe elbow in a stress and secondary stress calculation results. Elbow bend wall thickness increase after a stress most showed a trend of decrease, and the secondary stress showed a trend of increase, but a change of stress and secondary stress were not more than 20%. According to the specification, in the case of not consider accidental loading, a stress piping shall be conducted by the pipe pressure, gravity and other continuous load. Internal pressure is constant, there is no external load cases, the increase of thickness, stress strengthening coefficient decreases, and will cause the bend of a lower stress. Individual point due to the elbow wall weight increase, reduce the impact of the offset the stress strengthening coefficient, makes a stress rose slightly.
And in the absence of other secondary stress under the influence of cyclic loading is mainly caused by thermal expansion the joint torque generated in the cross section. As a result of the The wall thickness of elbow increases, the bend of the flexible coefficient K value is reduced, makes on the cross section of torque increase, so the secondary stress will increase.
2. The effects on thrust torque device interface
The wall thickness of elbow change push pipe of equipment interface of thrust and torque changes, pipe of high the influence of interface are discussed here.
By the calculation results can be seen that as a result of the The wall thickness of elbow increased, under the thermal state of resultant force and torque will increase, the biggest increase of 52.18%, the smallest is 14.76%. The reason is due to the changes of bend flexible coefficient. Flexible coefficient said bent pipe relative to the straight pipe under the bending moment increase flexible degree, its value is equal to the same deformation conditions, in accordance with the general and the bending moment and bending theory considering the bent pipe cross section to calculate the bending moment of the ratio of flat effect.
3. The impact on pipe, lifting point load
After The wall thickness of elbow change, in the piping of lifting point loading will change too.
By the calculation results can be seen that elastic bearing point of the steam extraction pipeline hot rate reached 15%, and drain piping hot load change rate is not more than 5%, the difference is mainly due to the different piping within the medium. Due to the drain pipe medium is water, bend weight is small, the proportion in the whole piping weight change not for piping lifting point load is too big change. But medium for steam of the steam extraction pipeline, density is small, elbow weight is bigger, the proportion in piping wall thickness change, will cause the tube department bearing load must be changed. But no matter how to load variation, spring support in terms of piping size spring jump phenomenon happens.
Source: Yaang Pipe Industry Co., Limited (

The advantages of Lap Joint Flanges

What Is a Loose Flange?
The advantages of Lap Joint Flanges
A loose flange (lap joint flange) is a device that is welded onto the end of a piece of pipe to create half of a flanged coupling. Consisting of a flat steel forging with bolt holes around the perimeter and an opening in the center the size of the pipe that is intended to be welded onto the loose flange, the component can be made of carbon steel or stainless steel to meet the intended application. There are loose flange types to fit elbows, valves and nearly every type of pipeline component in use.
Due to the nature of pipelines, the connections and couplings can rarely be constructed in advance. The use of a loose flange allows a worker to create a coupling in any location along the pipeline that is feasible. The worker simply cuts the pipe at the required location and places a loose flange onto the end of the pipe. After carefully preparing the pipe to weld, the loose flange is welded permanently to the end of the pipe. If a valve or elbow is required, the worker simply welds the flange onto the elbow or valve as well as the pipe, and the union is made.

Lap Joint Flanges have all the same common dimensions as any other flange named on this page however it does not have a raised face, they used in conjunction with a “Lap Joint Stub End”.
These flanges are nearly identical to a Slip On flange with the exception of a radius at the intersection of the flange face and the bore to accommodate the flanged portion of the Stub End.
Their pressure-holding ability is little, if any, better than that of Slip On flanges and the fatigue life for the assembly is only one tenth that of Welding Neck flanges.
They may be used at all pressures and are available in a full size range. These flanges slip over the pipe, and are not welded or otherwise fastened to it. Bolting pressure is transmitted to the gasket by the pressure of the flange against the back of the pipe lap (Stub End).
Lap Joint flanges have certain special advantages:

Freedom to swivel around the pipe facilitates the lining up of opposing flange bolt holes.
Lack of contact with the fluid in the pipe often permits the use of inexpensive carbon steel flanges with corrosion resistant pipe.
In systems which erode or corrode quickly, the flanges may be salvaged for re-use.

what is the advantage of the lap joint flange?

1. Because of the structure of a Lap joing flange ,  it can swivel around the stub end and pipe lining. When the piping system is assembe and disassemble frequently,  it is better to use a Lap joint flange. It means the flange can work even the two flanges bolt holes are misalignment . 

2. In a corrosive situation,  the flange joints need to be exchange very soon. To a lap joint flange, only the stub end is touch with the pipe and fluid , the backing flange no need to touch it .  It means you could only replace the stub end , no need to replace the backing flange , so the lap joint flange can decrease the cost of the piping systems.   

3.The backing flange and the stub end is seperated , so we can use two different materials for the two pieces.  it can work for  more complicated application.
Source: Yaang Pipe Industry Co., Limited (

The installation of high pressure piping must be strictly required

The high frequency vibration of high pressure piping has strict requirements on the assembly of the lens gasket of the high pressure flange. Before the assembly should be inside pipeline, pipe threaded end and tapered sealing surface, gaskets, high pressure flange and bolts, nuts and all the clean up, and check the appearance, when necessary, then coloring, magnetic or ultrasonic flaw detection. Any seals shall have crack; surface defects, which the pipe threaded end, high pressure flange, bolt and nut thread of the effective part of tooth high corrosion and wear shall not exceed 10% of the standard tooth height, each lap mechanical damage length should not be more than 1 / 5 of the perimeter, each circle and not larger than the circumference of a circle, bolt rod section shall not corrosion or mechanical damage; overproofed defects should be replaced in a timely manner. In the assembly process, attention should be paid to maintain a clean sealing surface, and strictly control the bolt of flange preload, the hydraulic tightening device or measuring torque wrench symmetric fastening.
Stud bolt tightening after the elongation control in general is not more than 3 / 10 000 bolt length, high temperature control between the 3 / 10 000 ~ 5 / 10 000 bolt length, bolt ends exposed outside the nut thread length should be equal as far as possible and not less than 2 times the pitch, to remove more than twice the bolt pre tightening force of around 6% increase. Installation shall not use forced assembly and a requirement to keep two flanges parallel to the end surface, the parallel deviation control within 0.3mm, keep the two flanges on the axial center line of the coaxial, coaxiality error depending on the diameter size control in less than 0.3 ~ 0.5mm range, to really confidential cover good contact and prevent bad moment. Keep a good surrounding environment, do a good job of dampproof, dustproof and anti rust and other maintenance work, and according to the working temperature of the level of discretion in the high pressure bolt coated powder lubricating oil or grease molybdenum disulfide. Pipeline running at high temperatures, the general should be in keeping the temperature test operation 24h after, tube pressure relief to 0.5MPa (gauge) following then moderate fastening force will flange bolts in hot tight to seal the pretightening force; pipeline running at low temperatures, in keeping the temperature test operation 24h after unloading despite internal pressure and with methanol on the surface of the bolts of flanges.
Source: Yaang Pipe Industry Co., Limited (

The four characteristics analysis of carbon steel butt welding flange

Carbon steel butt welding flange is not easy deformation, good sealing, widely used for in pipeline pressure or temperature fluctuations in the pipeline or high temperature, high pressure and low temperature, the advantage of cheaper prices and heat-resistant performance good we all know when working temperature of 75 degrees, the softening temperature of 135 degrees. Nominal pressure is not more than 2.5MPa; also used to transport the price is expensive, flammable, explosive medium pipeline, nominal pressure at PN16MPa or so. Carbon steel butt welding flange can in different areas and industries play an important role and value, can according to a certain way and numbering method, according to certain standards of production and use, to ensure to their in the use of the important role and contribution.
The four major characteristics of carbon steel butt welding flange:
1. Good insulation: carbon steel butt welding flange because of the low thermal conductivity of materials, 20 degrees Celsius heat conduction coefficient for 0.21-0.24W/mk, ratio of the steel tube, ultraviolet tube is much smaller, so the PP-R pipe insulation is good.
2. high impact: carbon steel butt welding flange because unique impact strength performance than other solid wall pipe have improved significantly, stiffness commensurate to 1.3 times the solid wall.
3. Long life: carbon steel butt welding flange pipe under the rated operating temperature and pressure, with anti – ultraviolet radiation, anti radiation.
Source: Yaang Pipe Industry Co., Limited (