DIN 1629 Seamless Steel pipe Of Non Alloys Steels are made of unalloyed steels, it's main grades are St 37.0, St44.0, St52.0.
Din 1629 seamless steel pipes application fields are: chemical plant, vessels, pipework construction and for common mechanical engineering purposes. Normally DIN 1629 standard are manufactured with no limiting working pressure values. Working temperature is limited below 300℃.
DIN 1629 is the standard specifies the Seamless Circular Tubes of Non Alloys Steels with Special Quality Requirements.
DIN 1629 applications the overheated boilers, as minimum thickness ferrite and seamless steel pipes, and as heat exchangers via austenitic pipes.
It is used for manufacturing pipeline,vessel,equipment,pipe fittings.
1.1 This standard applies to seamless circular tubes and pipes(hereinafter briefly referred to as "tubes") made of unalloyed steels as listed in table 1. These tubes are predominantly used in the constructin of chemical plant, vessels, pipework and for general mechanical engineering purposes. They are designed to meet high performance requirements. Normally there are no limiting vaiues or the maximum permissible working pressure of these tubes. The permissi l working temperature shall not exceed 300℃ are specified in Appendix A.)
The limits of application and other specifications given in this standard shall apply except in cases here other specifications are contained in codes of practice for specific fields of application, e.g. the Technische Regeln fur Dampfkessel (TRD) (Technical rules on steam boilers) or the Technische Regeln fur Druckbehalter (TRB)
(Technical rules on pressure vessels), AD-Merkblatter (AD Instrucation sheets).
| steel grade | Type of deoxidization (R, killed (including semi-killed)) (RR, fully killed) |
chemical composition, % by mass |
|||||
| Symbol | Material number | C | P | S | N¹) | Addition of nitrogen fixing elements (e.g.not less than 0,020% AItotal |
|
| St37.0 | 1.0254 | R | 0.17 | 0.040 | 0.040 | 0.009²) | - |
| St44.0 | 1.0255 | R | 0.21 | 0.040 | 0.040 | 0.009²) | - |
| St52.0³) | 1.0421 | RR | 0.22 | 0.040 | 0.035 | - | Yes |
1) A content in excess of the maximum value started is permitted if a phosphorus content less than the maximum specifled by 0,005% P per 0,001% N is observed. However, the nitrogen content shall not exceed a value of 0.012% in the cast analysis and 0,014% in the product analysis.
2) The specified maximum values do not apply if the steels are supplied with the RR (instead of R) type of deoxidization
3) The content shall not exceed 0.55% Si and 1,06% Mn in the cast analysis or 0,60% Si and 1,70% Mn in the product analysis
table 3. Amounts by which the chemical composition in the product analysis may deviate from the limiting values applicable to the cast analysis {see table2}
| Element | Amount by which the product analysis may deviate from the limiting values applicable to the analysis % by mass |
| C | +0,02 |
| P | +0,010 |
| S | +0,010 |
| N | +0,001¹) |
¹) A contant in excess of the maximum value stated is permitted if a phosphorus content less than the maximum specified by 0,005% P per 0,001% N is observed. However, the nitrogen contant shall not exceed a value of 0,012% in the cast analysis and 0,014% in the product analysis (this does not apply to the RR type of deoxidization.
table 4. Mechanical properties of tubes in the as delivered condition at room ternperature For wall thickness exceeding 65 mm, the values shall be agreed at the time of ordering
| Steel grade | Upper yield stress ReH for wall thicknesses, in mm, |
Tensile strangth Rm N/mm² |
Elongation after fracture A5 |
||||
|---|---|---|---|---|---|---|---|
| Symbol | Material number |
up to 16 | over 16 up to 40 |
over 40 up to 65 |
lonigtudinal | transverse | |
| St 37.0 | 1.0254 | 235 | 225 | 216 | 350²) to 480 | 25 | 23 |
| St 44.0 | 1.0256 | 275¹) | 265¹) | 255¹) | 420²) to 550 | 21 | 19 |
| St 52.0 | 1.0421 | 355 | 345 | 335 | 500²) to 650 | 21 | 19 |
| Grade | C max | Si max | Mn | P max | S max |
|---|---|---|---|---|---|
| St 35 | 0.17 | 0.35 | ≥0.40 | 0.025 | 0.025 |
| St 45 | 0.21 | 0.35 | ≥0.40 | 0.025 | 0.025 |
| St 52 | 0.22 | 0.55 | ≤1.60 | 0.025 | 0.025 |
| Steel grade | BK | BKW | BKS | GBK | NBK | |||||||
| Yield strength Rm N/mm min | Elongation% min | Yield strength Rm N/mm min | Elongation % min | Yield strength Rm N/mm min | Tensile Strength ReH N/mm min | Elongation % min | Yield strength Rm N/mm min | Elongation % min | Yield strength Rm N/mm min | Tensile Strength ReH N/mm min | Tensile Strength ReH N/mm min | |
| St35 | 480 | 6 | 420 | 10 | 420 | 315 | 14 | 315 | 25 | 340-470 | 235 | 25 |
| St45 | 580 | 5 | 520 | 8 | 520 | 375 | 12 | 390 | 21 | 440-570 | 255 | 21 |
| St52 | 640 | 4 | 580 | 7 | 580 | 420 | 10 | 490 | 22 | 490-630 | 355 | 22 |
¹) For cold f inished tube in the NBK condition (annealed above the upper transformation point under shielding gas or in a vacuum), minimum values of yield stress lower than these valued by 20N/mm² are permitted.
²) For cold finished tubes in the NBK condition, minimum values of tensile strength lower than these values by 10N/mm² are permitted.
Cold Drawn Seamless Mechanical Tubing (CDS) is a cold drawn 1018/1026 steel tube which offers uniform tolerances, enhanced machinability and increased strength and tolerances compared to hot-rolled products.
Cold drawn steel tube is with hot-rolled steel coil as raw material, and tandem cold rolling pickled to remove oxide scale, its finished rolling hard roll, rolling hard volumes due to the continuous cold deformation caused by cold hardening strength, hardness increased indicators declined tough plastic, stamping performance will deteriorate, which can only be used for simple deformation of the parts.
Rolling hard roll can be used as the raw material of the hot-dip galvanizing plant, hot dip galvanizing line set annealing line. Rolling hard roll weight is generally 6 to 13.5 tons, the coil diameter of 610mm.
Hot-rolled seamless steel pipe production base deformation process can be summarized as three stages: perforation, extension and finishing.
The main purpose of the perforation process is to become a solid round billet piercing hollow shell. Capillary in the specifications, accuracy and surface quality can not meet the requirements of the finished product, further improvements are needed to deform the metal through. The main purpose of the stretching machine is further reduced sectional view (main compression wall) for a larger axial extension, so that the capillary improved dimensional accuracy, surface quality and organizational performance.
After stretching machine rolled steel pipe shortage collectively need further molding mill in order to achieve the requirements of the finished pipe. Rolled steel due to pass in the method widely used in the production of seamless steel tubes.
So far, due to the method pass rolling steel can be divided into two categories: core pension without rolling rolling (hollow body rolling), and with the mandrel. Sizing machines, reducing mill and stretch reducing mill belonging to the hole without mandrel type continuous rolling mills are generally coffin. Its main purpose is to reduce the diameter of the deformation process or sizing get finished steel, the wall thickness of process control, can make thinning, thickening or nearly unchanged.
All the traditional hole-type rolling machine with mandrel belong to extend machine. The main purpose is to reduce the deformation process perforated capillary wall thickness and outer diameter roll passes in the deformation zone and the mandrel posed, for a larger axial extension. At the same time a certain improvement in the organization, performance, accuracy, surface quality.
Before cutting pipe and tubing
No matter the material, measure the diameter of the pipe or tube to be cut to ensure that you use the right-size tube cutter for the job. When determining how to make a straight cut, use a tape measure and a pencil or other writing instrument to mark on the surface where you want to cut. If possible, mark around the circumference of a pipe, especially when cutting with a handsaw. Ensure that a cut is as straight as possible by securing the pipe with a vise, clamp, miter box or even duct tape to keep the length from shifting out of place while cutting.
After cutting pipe and tubing
The production equipment consists of punching machine, automatic pipe rolling machine, coiling machine, sizing machine and reducing machine. The round tube is inserted into the hollow of the thick-walled tube, and the axes of the two rollers form an oblique angle with the rolling line. In recent years, the inclination angle has increased from 6° to 12° to 13° to 17°, increasing the speed of the punch. When producing structural seamless pipe with a diameter greater than 250mm, secondary perforation is used to reduce the thickness of the hollow billet wall. New technologies have also been developed to enhance the perforation process and improve the quality of the capillary.
The production equipment includes punching machine, continuous rolling mill, and tension reduction machine. The round billet is pierced into a hollow billet, then inserted into the mandrel, and continuously rolled by 7 to 9 two-roll mills. After rolling, the mandrel bar is taken out and reheated to reduce tension. In 2014, the annual output of 140mm continuous rolling mills is 0.4 to 600,000 tons, which is 2 to 4 times that of plug mills. The characteristics of this unit are suitable for the production of steel pipes with a diameter of 168mm or less. However, the equipment investment is large, the installed capacity is large, and the processing and manufacturing are complex.
Three-roll rolling production is mainly used to produce thick-walled seamless steel pipes with high dimensional accuracy. The wall thickness accuracy of the seamless steel pipe produced by this manufacturing process can reach plus or minus 5%, and the pipe accuracy is twice that of the seamless steel pipe produced by other methods. This manufacturing technique developed rapidly with the invention of the new three-high skew rolling mill in the 1960s. The new type of rolling mill is characterized by rapidly rotating the inlet rotary rack to change the expansion angle of the tail, thereby preventing the triangle from appearing at the tail, and expanding the ratio of the outer diameter to the wall thickness of the production varieties from 12 to 35, which can not only produce thin-walled seamless welded steel pipes , but also can improve production capacity.
The peeled round base is first perforated or expanded, then heated by induction heating or a salt bath, coated with lubricant, and loaded into the extruder. The metal is squeezed into the pipe through the circular gap between the mandrel and the tip of the pen. This manufacturing process is mainly used for the production of superalloy tubes, specialty tubes, composite tubes and non-ferrous metal tubes. It has a wide range of production but low volumes. The production of extruded tubes has also grown in recent years due to improvements in die materials, lubricants and extrusion speeds.
This manufacturing process is used to produce small-diameter precision-shaped thin-walled low-carbon steel pipes. It is characterized by the use of multi-stage cycle manufacturing technology. In the 1960s, it began to develop in the direction of high speed, multi-line, long stroke and long tube blank. In addition, small roller mills have also been developed, mainly for the production of precision tubes with a thickness of less than 1mm. The cold rolling equipment is complex, the tool processing is difficult, and the specification conversion is not flexible. And usually a combined process of cold rolling and cold drawing is used, that is, cold rolling is used to reduce the wall thickness to obtain larger deformation, and cold drawing technology is used to obtain various specifications.
Alloy steel pipes are ideally suitable for chemical, petrochemicals, and other energy-related applications.
The alloy steel pipe adopts high quality carbon steel, alloy structural steel and stainless & heat resisting steel as raw material through hot rolling or cold drawn to be made.
Alloy steel can be used in process area where carbon steel has limitation such as
As an important element of steel products, alloy steel pipe can be divided into seamless steel pipe and welded steel pipe according to the manufacturing technique and tube billet shape.
Here you can see the common alloy steel grade that you will come across.
Why the application of alloy steel pipe is wider than others
There are many kinds of materials used for transport in industrial production. Specifically we will have more choices and it is not limited to the use of alloy steel pipe. But even in the face of more choices, many people tend to choose alloy steel pipe. People make their own choices will have their own reasons. This means the alloy steel pipe application has its own advantages. Compared with transmission lines made of other materials, after it meets the basic application requirements, its quantity is lighter. Then in the practical application of alloy steel pipe, it will have more advantages because of this. Besides its physical characteristic advantage, it also has economic advantages. The wide application of alloy steel pipe is with kinds of reasons. So in practical usage, we can exploit the advantages to the full, in this way can we get more profits in these applications of alloy steel pipe.
The transportation of kinds of gases or liquids in production needs to rely on alloy steel pipe. This shows that the actual role of alloy steel pipe application is important. High temperature resistant and low temperature resistant is the tolerance of temperature. In the practical application of alloy steel pipe, there will be many materials need to be transported. However their temperatures are not the same. So this can be the basic requirement to alloy steel pipe. It needs more corrosion resistance. Corrosion resistant material is the best material during transporting, because it is corrosion resistant. So it can be used in more occasions. And it is definitely very convenient for users.
Can be 100% recycled, environmentally friendly, energy-saving, resource conservation, national strategy, national policy to encourage the expansion of the field of application of high-pressure alloy pipe. Of alloy steel pipe total consumption accounted steel in the proportion is only half of the developed countries, to expand the field of use of the alloy steel pipe to provide a wider space for the development of the industry. The future needs of the average annual growth of China’s high-pressure alloy steel pipe long products up to 10-12%.
Alloy Steel pipe contains substantial quantities of elements other than carbon such as nickel, chromium, silicon, manganese, tungsten, molybdenum, vanadium and limited amounts of other commonly accepted elements such as manganese, sulfur, silicon, and phosphorous.
Our team of experienced sales specialists proudly partners with gas and chemical processors, power generation plants, oil refineries, and related industries to offer piping components and value-added services.
The biggest advantages of alloy steel pipe can be 100% recycled, environmentally friendly, energy-saving, resource conservation, national strategy, national policy to encourage the expansion of the field of application of high-pressure alloy pipe. Of alloy tube total consumption accounted steel in the proportion is only half of the developed countries, to expand the field of use of the alloy tube to provide a wider space for the development of the industry. According to the Chinese Special Steel Association alloy pipe Branch Expert Group, the future needs of the average annual growth of China’s high-pressure alloy pipe long products up to 10-12%.
Steel pipe delivery status(condition): cold / hard (BK), cold / soft (BKW), after cold stress relief annealing (BKS), annealing (GBK), normalized (NBK).
| Term | Symbol | Explanation |
| Cold-finished/hard (cold-finished as-drawn) | BK | No heat treatment after the last cold-forming process. The tubes therefore have only low deformability. |
| Cold-finished/soft (lightly cold-worked) | BKW | After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits. |
| Annealed | GBK | After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum. |
| Normalized | NBK | The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum. |
The general cold strip mills, volume should go through continuous annealing (CAPL unit) to eliminate cold hardening and rolling stress, or batch annealing reach the mechanical properties of the corresponding standard specifies. Cold rolled steel surface quality, appearance, dimensional accuracy better than hot-rolled plate, and right-rolled thin product thickness is about 0.18mm, so the majority of users favor.
Cold rolled steel coil substrate products deep processing of high value-added products. Such as electro-galvanized, hot dip galvanized, electro-galvanized fingerprint resistant, painted steel roll damping composite steel, PVC laminating steel plates, etc., so that the excellent quality of these products has a beautiful, high resistance to corrosion, has been widely used.
Cold rolled steel coil finishing after annealing, cut the head, tail, trimming, flattening, smooth, heavy volume, or longitudinal clipboard. Cold-rolled products are widely used in automobile manufacturing, household electrical appliances, instruments, switches, buildings, office furniture and other industries. Steel plate strapping package weight of 3 to 5 tons. Flat sub-volume typically 3 to 10 tons / volume. Coil diameter 6m.
Bare packing/bundle packing/crate packing/wooden protection at the both sides of tubes and suitably protected for sea-worthly delivery or as requested.
There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security.
Our packing can meet any needs of the customers.
Commonly used alloying elements and their effects are listed in the table given below.
| Alloying Elements | Effect on the Properties |
|---|---|
| Chromium | Increases Resistance to corrosion and oxidation. Increases hardenability and wear resistance. Increases high temperature strength. |
| Nickel | Increases hardenability. Improves toughness. Increases impact strength at low temperatures. |
| Molybdenum | Increases hardenability, high temperature hardness, and wear resistance. Enhances the effects of other alloying elements. Eliminate temper brittleness in steels. Increases high temperature strength. |
| Manganese | Increases hardenability. Combines with sulfur to reduce its adverse effects. |
| Vanadium | Increases hardenability, high temperature hardness, and wear resistance. Improves fatigue resistance. |
| Titanium | Strongest carbide former. Added to stainless steel to prevent precipitation of chromium carbide. |
| Silicon | Removes oxygen in steel making. Improves toughness. Increases hardness ability |
| Boron | Increases hardenability. Produces fine grain size. |
| Aluminum | Forms nitride in nitriding steels. Produces fine grain size in casting. Removes oxygen in steel melting. |
| Cobalt | Increases heat and wear resistance. |
| Tungsten | Increases hardness at elevated temperatures. Refines grain size. |
Ceramic lined pipe is made through self-propagating high-temperature synthesis (SHS) technique.
Cast basalt lined steel pipe is composed by lined with cast basalt pipe, outside steel pipe and cement mortar filling between the two layers.
Ceramic tile lined pipes have very uniform coating of specially formulated ceramic material that is affixed to the inner of the pipe.
The material of the rare earth alloy wear-resistant pipe is ZG40CrMnMoNiSiRe, which is also the grade of rare earth alloy steel.
Tubes Erosion Shields are used to protect boiler tubing from the highly erosive effects of high temperatures and pressures thereby greatly extending tube life.
The ASTM A213 T91 seamless tubes are primarily used for boiler, superheater, and heat-exchanger.
