So when we say thermal expansion pipe usually it is referred to the pipe made in seamless. Since it is preferred to use seamless pipe than welded pipe in some pipelines or modern constructions, thermal expansion pipe is a divine option to the people who regularly need a good quality steel pipe.

thermal expansion manufacturing processes

The production process of the thermally expanded steel pipes is consisting of few steps.

Original seamless manufacturing part

1.The main raw material in case of producing the seamless thermal expansion pipes is steel. Steel is obtained from iron. There may be other materials that can exist along with the steel. For example, manganese, aluminium, zirconium etc.

2.The next step after the raw steel is to turn them usable steel. Well, whether it is the production process of welded or seamless pipes, the starting occurs at the casting of the raw steel into a more workable form. The molten steel is obtained by the melting of the iron ore along with coke in a furnace. Then the carbon is removed by the help of blasting oxygen in liquid. The molten steel is then poured into iron moulds to get ingots.

3.Next, the ingots are putted in a machine where it is pressed and turned into thinner and longer pieces of steel. The thinning and elongation process continues till the desired size of the steel is obtained. The steel is flipped so the steel is even on both sides.

4.The later process is the cutting of the uneven ends. Here, both the uneven ends are cut off and the blooms are cut off into shorter pieces. These blooms are then processed further to make the thermal expansion pipe.

Hot rolled part

5.It is then turned into a pipe by the stretching of the steel out. In case of the seamless pipes, the primary concern is to, stretch the steel and form it into a pipe. The round billets are heated to around 1204 degree Celsius. The steel reach to such state where it is easy to stretch. The stretching is done with the help of a special type of roller.

6.Then next is spraying water on the hot pipes. For taking them back to the normal stage, cold water is sprayed evenly on the pipes. The pipes are then painted or given finishing for a good outer look.

Thermal Heated Part (Hot expanding processes)

Because of the limits from seamless steel pipe manufacturers, the largest hot rolled seamless pipe normally below 457 mm, or 508 mm. So if you are seeking for the seamless pipe larger than this dimensions, we have to do hot expansion to the original (mother) seamless pipe. So another of thermal expansion pipe is coming into market.

It is to use the heat generated from mid-frequency heating machine, expanded by a expansion equipment, expanding pipe to a certain diameter that we required.

With the advantages of high efficiency, lower cost and seamless quality, this type of thermal expansion seamless pipe has been quickly accepted by the customers worldwide.

Requirements for thermal expansion pipe is increasing

The uses of thermal expansion pipe are increasing day by day. Though the price is a bit higher than the welded ones but it is more beneficial to use them because they are not just safe and reliable but will also go a long way.

In most cases large diameter steel pipe is made in welded like LSAW pipe or SSAW pipe; More over, it also could be made in seamless by using hot expanding processes.

It shall be noted that for a high pressure pipeline large diameter seamless pipe is preferred. Since in welded type it is not expected as seamless types to bear the big pressure (the weakest point of the welded pipe is the welded seam on it). The welded seam can break or crack at anytime hence, people are looking for seamless large pipes for various things.

Material Standard

Almost all the steel material could used for making large diameter pipe, listed as blow for Carbon Steel, Chrome Moly Alloy pipes:

API 5L B, X42, X46, X52 to X80.
ASTM A53B
ASTM A252 Grade 2, 3
ASTM A671
ASTM A672
ASTM A691
ASTM A106B

Large Diameter Stainless Steel Pipe

Large diameter stainless steel pipe also required for a lot of industries, for liquid transmission, machine parts make. Mostly made in tig weld, material standard ASTM A312 or EN 10088-3. Grades in:

TP304/L/H, S30400, S30403, S31409
TP316/L/H, S31600, S31603, S31609
TP310S/H, S31008, S31009
TP321/H, S32100, S32109
TP347/H, S34700, S34709
904/L

Large diameters refer to pipe above 457 mm (16 inch) and 508 mm (20 inch)

As we know maximum diameters for ERW pipe usually is 457 mm 16 inch, so we can say the pipe diameters is larger than this OD are known to be large diameters pipes.

For LSAW and SSAW large steel pipe: From 508 mm 20 inch to 2540 mm 100 inch.

For large diameter seamless pipe also refer to the pipe that more than 16 inch or 20 inch. Since the pipe larger than these sizes, will not be manufactured only by hot rolling, an additional process hot expanding will be applied. This way could enlarge the pipe diameters in a short time, with low cost and high efficiency, therefor it has became a modern way of manufacturing large seamless pipes.

Hot expanding

Hot expanding process also known by thermal expansion process. It is to heat the pipe into a near transformation temperature, use corner skew rolling method or hot drawing method to expand seamless pipe diameters.

Notes before purchase large diameter seamless pipe

If you do not have ideas about the large diameter seamless pipe then it is very hard to buy one with good quality. Therefore, it is very important to know about it before purchasing.

1. Must not have seam on pipe body.

The seamless pipe must not have weld seam (some people remove the seam in an undetectable way and be careful of this). Large diameter seamless pipe shall be constructed in a specific process. Raw material should be a solid and round billet. Then, the billet is heated at a very high temperature but one should be careful while doing so because if the temperature rises to melting point then billet may melt. The billet after heating is stretched and pulled over until it takes the shape of a hollow tube. As the welded pipes are conventional, your contractor may suggest you to buy the welded ones but you have to be very careful and choose the seamless large pipe.

2. Roundness shall be noted

The next thing is the uniformity of shape of the seamless pipe. As the welded seam pipes are wrapped around another form before welding and as welding needs stress, heat and other external variables for the whole process of forming, it is very tough to get a welded pipe that is exactly round in shape. The seamless steel pipe is the continuous extrusion of alloy which signifies that you will just a get a round cross section that is necessary when you are using them for any construction process or installing pipes.

3. Large Seamless pipe bear big pressure than large welded pipe

The strength of the seamless pipe is more than the welded pipes. Well, you might find it quite expensive but, trust our examination; this is more reliable even under pressure. The welded pipes have the chance to break when in pressure but you can trust the large diameter seamless pipe without any doubt. The empty pipes always support of its own weight but when the pipe is filled with material or under load, it also supports the weight as well. Mostly leaks and pipe failures occur in case of the welded pipes. The seamless pipes does not have the seam hence, there is no chance of pipe failure.

4. Big diameter seamless pipe can working in harsh conditions

One of the best attributes of the seamless large pipes is that, it has the capability to work under extremely cold or extremely hot environment whereas, it is quite impossible for the welded pipes to work in extremely harsh condition.

Cost differences for large diameter pipes in different types

Large seamless pipes after hot expanding, the price is lower than normal hot rolled seamless pipe, (steel density reduced). But is higher than large welded pipes like SSAW and LSAW pipe.

Though the price of the large diameter seamless pipe is bit higher than the welded ones but the increasing ability and benefits are making it appropriate for any usage. In the array of commercial application of pipes, the importance of the seamless large pipes are increasing including pipelines oil rigs, building of ships, offshore rigs, machinery parts, pressure vessels, parts of machineries, equipment of oil field etc.

ASTM A106 Grade B pipe is considered equivalent to ASTM A53 Grade B and API 5L Grade B in terms of chemical composition and mechanical properties. It is a type of carbon steel that has a minimum yield strength of 240 MPa and a minimum tensile strength of 415 MPa.

Below, we will explain ASTM A106 Grade B pipe from different aspects:

Chemical composition
Mechanical Strength
Dimensions
Material specification
Standards referred for making A106 pipes
Grade types
A Specific order description

ASTM A106 Standard Specification

ASTM A106 standard specification in PDF.

Chemical composition and Mechanical Strength

ASTM A106 Grade B and A pipe chemical composition

Chemical composition in %

Carbon (C) Max For Grade A 0.25, For Grade B 0.30, Grade C 0.35
Manganese (Mn): 0.27-0.93, 0.29-1.06
Sulfur (S) Max: ≤ 0.035
Phosphorus (P) : ≤ 0.035
Silicon (Si) Min : ≥0.10
Chrome (Cr): ≤ 0.40
Copper (Cu): ≤ 0.40
Molybdenum (Mo): ≤ 0.15
Nickel (Ni): ≤ 0.40
Vanadium (V): ≤ 0.08

Please note:
For every reduction of 0.01% in the maximum carbon element, an increase of 0.06% in manganese above the specified value is allowed, up to a maximum of 1.35%.

Elements Cr, Cu, Mo, Ni, V combined shall not exceed 1%.

ASTM A106 Grade B Tensile Strength and Yield Strength

Elongation formula:
In 2 in. [50mm], shall be calculated by: e = 625 000 A^0.2 / U^0.9
For inch-pound Units, e = 1940 A^0.2 / U^0.9

Explanations of e, A, and U, please find here. (Equation same with ASTM A53, API 5L pipe.)

Tensile Strength, min, psi [MPa] Grade A 48,000 [330], Grade B 60,000 [415], Grade C 70,000 [485]
Yield Strength minimum at psi [MPa] Grade A 30,000 [205], B 35,000 [240], C 40,000 [275]

Elongation in 2 in (50mm), minimum percentage % ,
For all small sizes tested in full section, basic minimum elongation transverse trip tests: Grade A Longitudinal 35, Transverse 25; B 30, 16.5; C 30, 16.5;
In case standard round 2 inch gage length test sample is used, above values are: Grade A 28, 20; B 22, 12; C 20, 12.

ASTM A106 Grade B Pipe Dimensions Schedule

The standard covers pipe sizes in NPS (National Standard Straight) from 1/8 inch to 48 inches (10.3mm DN6 – 1219mm DN1200). It also complies with the nominal wall thickness specified in ASME B 36.10M. For sizes that are not covered by ASME B 36.10M, this standard specification can still be used.

Raw materials

The materials used for the ASTM A106 standard specification should be suitable for bending, flanging, or similar forming processes. If the steel material is to be welded, the welding process should be appropriate for this grade of ASTM A106 and suitable for high-temperature working environments.

In cases where a superior or higher grade of ASTM A106 steel pipe is required, the standard provides an optional specification for supplementary requirements. Additionally, these supplementary specifications require additional testing to be conducted when placing an order for pipes that adhere to this standard.

Standards referred for making ASTM A106 pipes

References ASTM standards:

a. ASTM A530/ A530M: This is the standard specification for the common requirements of carbon and alloy pipes.
b. E213: The standard for the Ultrasonic Examination test.
c. E309: The standard for the Eddy Current examination test.
d. E381: The standard for the plan of Macroetch test, for steel products such as steel bars, steel billets, blooms, and forging steels.
e. E570: The standard for the test plan for the flux leakage test of ferromagnetic steel pipes and pipeline products.
f. Related ASME Standard:
g. ASME B 36.10M: The standard specification for nominal sizes of welded and seamless steel pipes.
h. Related Military standard:
i. MIL-STD-129: The standard for the markings of shipment and storage.
j. MIL-STD-163: The standard for the storage and shipment of steel forging products.
k. Related federal standard:
l. Fed. Std. No. 123: The standard for the marking and shipments for civil agencies.
m. Fed. Std. No. 183: The standard specification for continuous ID marking for steel products.
n. Surface standard:
o. SSPC-SP 6: The standard specification for surface preparation.

Grade B Seamless Pipe

The ASTM A106 standard specifications for seamless steel pipes consist of three grades: ASTM A106 Gr. A, Gr. B, and Gr. C. With higher-grade materials, the strength performance is improved.

Test Methods

The test methods for ASTM A106 grades A, B, and C include flattening tests, hydrostatic tests, nondestructive electric tests, ultrasonic tests, eddy current tests, and flux leakage tests. These test procedures should be communicated and confirmed with the client to determine which specific tests will be applied.

Our Supply Range for Sale

Octal supplys ASTM A106 Grade A, Grade B, and Grade C seamless carbon steel pipes under the following conditions:

Standard: ASTM A106, Nace, Sour service.
Grade: A, B, C
Range of OD outer diameter: NPS 1/8 inch to NPS 20 inch, 10.13mm to 1219mm
Range of WT wall thickness: SCH 10, SCH 20, SCH STD, SCH 40, SCH 80, to SCH160, SCHXX; 1.24mm up to 1 inch, 25.4mm
Range of length: 20ft to 40ft, 5.8m to 13m, single random lengths of 16 to 22ft, 4.8 to 6.7m, double random length with average 35ft 10.7m
Ends procession: Plain end, beveled, threaded
Coating: Black paint, varnished, epoxy coating, polyethylene coating, FBE and 3PE, CRA Clad and Lined.