to success
since 1997

Distributor / authorized representative that deals with supply & delivery of equipment for machining pipe billets and slabs to industrial enterprises of Russia

Engineering company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), Russia, has been successfully working with a number of Russian industrial enterprises at the local market for more than 20 years. Since the company’s founding, it has acquired immense engineering experience, market reputation, and has realized more than a hundred large-scale projects at the industrial plants in Russia. Our company is continuously in search of new business partners, who consider Russian market investment-attractive and want to boost their sales in the region, as well as expand their field of activities and enter a new international level. 

We are interested in cooperation with the manufacturers of , who are looking for an official and reliable distributor that deals with supply & delivery of their equipment to the industrial plants in Russia.

The company’s top management and sales team are well acquainted with the Russian market, its mentality and laws; they also understand industrial specifics of the financial and economic activities of the Russian customers. All our sales managers have a large customer database, extensive experience of successful sales and well-established connections with the potential buyers of your pipe billets / slabs machines. This allows our managers to promptly set out the most promising directions for promotion and to ensure a rapid entry of the products into the promising Russian market. Our employees, who are fluent in English and German, are focused on working at the international market with the supplies of foreign equipment.

Our team of experienced engineers, who can handle the most serious technical problems, constantly keeps in touch with the Russian customers, holds meetings and delivers presentations regarding the latest achievements of our manufacturing partners. They point out the engineering challenges and actively communicate with all the departments at Russian plants. That is why the specifics of doing a business in the Russian Federation are well-known to us, and we also know the equipment of the local industrial plants and their up-to-date modernization needs.

Once we become your authorized representative in Russia, our marketing staff will carry out a market research in order to check the demand for pipe billets / slabs machines, will submit a market overview for pipe billets / slabs machines that you offer and evaluate the needs for this type of equipment at local plants. Our specialists will also estimate the potential and capacity of this market at local industrial plants. Our IT-team will start developing a website for your products in Russian. Our experts will assess the conformity between your pipe billets/slabs machines and customer needs as well as analyze the common reaction to the new goods in general. We will look into the categories of potential customers, and pick out the largest and the most promising plants.

Upon becoming your authorized agent on the territory of Russia, ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), will obtain certificates, if required, for a batch of the goods, for various types of pipe billets / slabs machines in compliance with Russian standards. We can also arrange the inspection in order to obtain TR TS 010 and TR TS 012 Certificates. These certificates provides permission to operate your equipment at all industrial plants of the EAEU countries (Russia, Kazakhstan, Belarus, Armenia, Kyrgyzstan), including the hazardous industrial facilities. Our company is eager to assist in issuing Technical Passports for pipe billets / slabs machines as per Russian and other EAEU countries’ requirements.

Our engineering company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), collaborates with several Russian design institutes in various industrial segments, which allows us to conduct preliminary design as well as subsequent design works according to the standards, construction rules and regulations that are applicable in Russia and other CIS countries. It also enables us to include your pipe billets machines into the future projects.

The Company has its own logistics department that can provide packing service, handling as well as the most efficient and cost effective mode of transportation of the goods (incl. over dimensional and overweight goods). The goods can be delivered on DAP or DDP-customer’s warehouse basis in full compliance with all the relevant regulations and requirements that are applicable on the Russian market.

Our company has its own certified specialists who will carry out installation supervision and commissioning of the delivered equipment, as well as further guarantee and post-guarantee maintenance of slabs machines. They will also provide necessary training and guidance for the customer’s personnel.

General description

A series of operations involving preparation of pipe billets for piercing is intended to ensure a satisfactory condition of the external surface, the required billet specified or multiple length and high-quality centering of its exposed face.

High-quality preparation of the billet for piercing significantly influences the hollow billet surfaces (external and internal), their thickness, and curvature.

This equipment includes shears for various kinds of cutting (shear cutting, cold breaking, circular sawing, etc.), equipment for centering the billet, heating furnaces (ring, rotary-hearth furnaces, pusher sectional, travelling-hearth furnaces); it can also include the equipment for piercing a billet into a hollow billet.

Basic inspection and repair methods for an incoming billet and the equipment used

The incoming pipe-rolling billet surface can have defects caused by previous processing.

The defects of the billet surface can be:

  • a result of steelmaking: cracks, tears, scabs, non-metallic inclusions;
  • heating defects: overheating and burning;
  • rolling defects: rolling laps, ridges.

The percent of defects resulted from rolling is 20 ‑ 30%. As a rule they are located under scale. The following methods are used to find out them: 1 – visual inspection method; 2 – magnetic-particle, luminescent, dye-penetrant, electric induction methods. The most common and simplest method is visual inspection, but it requires preliminary cleaning; moreover, the method itself is very laborious.

The surface is cleaned from scale by etching in acid solutions (mixture) using sand- and shot-blasting method and using metal brushes (wire brushing). To perform visual inspection the billet surface is lightly grinded with emery stone over the helical curve, so called “serpentine”. Such a serpentine allows detecting longitudinal and transversal cracks and hair cracks.

However, preparation of ingots for rolling causes more problems as their surface has more defects in comparison with other incoming billets. In this case, the defects are removed from the ingot’s surface prior to piercing or from the pipe’s surface without any preliminary machining.

According to the first method, the ingots totally cooled down after teeming are conditioned, and afterwards, they are feed into heating devices. This method is feasible when the increased requirements are specified to quality of rolled products surface (for example, when rolling the pipes from alloyed steels).

The second method is used in case of hot charge when ingots (still hot) are placed into heating devices.

The advantages of the first method are as follows:

  • possibility to remove the defects from significantly smaller surfaces in comparison with the second conditioning method because the surface of the billet is significantly larger than that of the ingot. As the ingot weight increases and the billet section decreases, the method becomes more advantageous;
  • if the defect is completely removed from the ingot surface, we will obtain a finished product with a cleaner surface because the billet rolled from non-cooled ingots not only gets a rolling-origin defect but also retains the steelmaking ones.

In practice, the two-stage method for removing the defects from metal surface is used:

  • first, the ingot and then the billet are conditioned;
  • rough defects are removed from the ingot surface and the other defects are removed from the billet surface.

Such method ensures the maximum surface condition of the finished product.

For the maximum allowable depth of the defects to be removed by repair, see Table 1.

Table 1. Depth of defects in ingots.

Ingot diameter, mm Depth of the defect, mm
345/330 30
385/370 30-35
450/435 35-45
547/531 90-40
615/600 90-45

The conditioning can be either total or selective. When performing the total conditioning, a metal layer is removed on the outside. It is used in case there are numerous defects on the surface of an ingot, bloom or a billet. The selective (local) conditioning is used for removal of the defects distributed fragmentarily over the metal surface. Such conditioning causes less loss of metal in comparison with total conditioning.

Total conditioning is performed by flame scarfing, grinding and cutting methods on flame scarfing, ingot-peeling, centerless turning and milling machines.

The local conditioning is performed by flame scarfing using a hand-held acetylene cutter, with a swing frame grinder or by chipping with an air-operated chisel.

Sometimes, a combined method for removing the defects is used. The method of conditioning the surface of ingots, billets and finished pipes is to be chosen based on the grade scale of the defects on the surface (their area and depth), nature of defects, characteristics of the ingots to be conditioned as well as on the following main characteristics of the metal to be treated: cross-sectional dimensions, physical properties of the material to be treated, purpose of the finished product, and nature of the subsequent processing.

When choosing the method for removing the surface defects, the following factors should be taken into consideration:

  • the defects from the ingot surface are to be removed before rolling;
  • when removing the defects, the maximum effect is achieved when using the combined method, i.e. conditioning before and after rolling;
  • total conditioning is useful in case when the metal surface has a high degree of damage; while local (selective) conditioning is useful if the defects are distributed fragmentarily over the metal surface;
  • flame scarfing is useful to prepare the ingots and continuously cast billets of soft, carbon, low-alloy and alloy steels as well as high-alloy steels with large cross sections for rolling;
  • conditioning by grinding is applied to pipe billets (continuous conditioning) of corrosion-resistant steels, the ingots of which contain a large number of surface defects, without preliminary conditioning of them on machines; the ingots and billets of high-alloy steels, which are difficult to be machined and contain a large number of relatively fine defects;
  • chipping with an air-operated chisel is applied to remove local defects with the depths of 3 ‑ 4 mm on ingots and continuously cast billets; as well as to remove defects from a finished pipe of large section unless such conditioning would reduce the finished pipe profile dimensions above the tolerance;
  • selective conditioning on milling machines is performed to remove deep fragmentary defects on ingots and billets of alloy steels as well as to replace an  underproductive and heavy labor method “chipping” by milling;
  • billets and finished rolled products with a round cross section, ingots of high alloy steels and slabs with a high rate of surface defects should be completely peeled or milled.

Basic methods for total conditioning of the incoming billet surface

Flame scarfing is one on the most common techniques for removal of surface defects. This method is used to remove both local defects and defects of the whole surface layer of rolled products. Flame material scarfing is based on the iron’s ability to ignite in an oxygen jet at a temperature below the melting point.

The place to be scarfed is preheated by gas-oxygen flame up to 1050°С, and then the pure oxygen jet is directed to the metal surface along the product. The surface steel layer burns down under the fed oxygen jet, and then the defective metal layer is removed. Burning of steel releases much heat. This heat together with that of the preheating flame allows speeding up the metal burning process and keeping it continuously. The process of surface layer burning is so quick that the heating of metal main mass causes no changes of structural pattern of steel and its mechanical properties. The possibility of patch work and the danger of surface decarburization are excluded.

Flame scarfing is used for ingots and continuously cast billets. The productivity of flame scarfing exceeds that of other methods. Flame scarfing can be used for killed, low- and medium-alloy steels.

Conditioning by abrasive wheels (grinding) is commonly used for removing the defects from surface of a billet (especially, a billet of alloy or high-allow steel).

Conditioning by grinding for rolled products and ingots is an expensive method; however, it is widely spread in metallurgy.

Conditioning by grinding is one of the kinds of metal cutting. The cutting tool (abrasive wheel) consists of grains made of hard abrasive substances cemented together by a binder. Abrasive cutting is similar to milling. The abrasive grains work like mill teeth; however, the number of grains on the abrasive wheel is significantly higher than the number of the mill teeth. Besides, the edges of the abrasive grains are oriented differently and do not have a more favorable cutting angle. Therefore, only a minority of grains cuts the metal while a majority of them rubs against metal or scrapes it. The noted peculiarity of the cutting process causes a large quantity of heat to be released during conditioning by grinding.

The following factors influence the productivity of conditioning by grinding: properties of an abrasive wheel, cutting rate, i.e. (abrasive) wheel surface speed, hardness, viscosity, quantity, and nature of defects of the metal machined. The stationary abrasive peeling machines are used to perform the total conditioning by grinding.

Conditioning on metal-cutting machines. This procedure is performed by means of peeling (turning) and milling. This method is usually used to condition ingots, continuously cast billets, finished pipes of high alloy steels and pipe billets made of other steel (of critical purpose), for example, if their surfaces have a large number of defects or deep fragmentary flaws (in ingots, billets).

The most reliable method to remove the defects from an ingot and a continuously cast ingot is continuous peeling of their surface when the continuous removal of the surface layer is performed.

The continuous peeling method is used to remove a large number of defects from ingots and billets of all kinds of steels including those with a high content of Cr, Ni, Ti and Al. Depending on weight and grade of steel, 5 ‑ 18% of metal are lost while peeling an ingot and 12 ‑ 25% of metal are lost while peeling a round billet. Peeling can be used for the ingots with the weight of 0.2-5 t of both round and square shape.

Square ingots are peeled on special machines (using one or two cutters) and round ingots are peeled on usual or special heavy-duty lathes. It is better to peel the tetrahedral ingots with small rounding radius at the corners on the machines equipped with a movable support, thus prolonging the service life of the cutter and ensuring the maximum turning capacity. The design of such machines allows peeling the ingots with constant cutting angles because the cutter holders perform swinging motion during the operation. This can be performed due to the mechanism that swings the cutters and a master plate on the machine support. When peeling the ingots, the cutting depth is 2-20 mm and more, depending on the defect location depth.

Pipe billets and round rolled section steel are peeled on special peeling machines and screw lathes. Rolled and forged billets to be peeled should comply with the following specifications:

  • curvature: max. 3 mm per meter of length of a round billet with the diameter of up to 130 mm and max. 5 mm for a billet with the diameter of over 135 mm;
  • cutting obliquity in case of hot saw cutting is up to 3°.

After peeling, the billets should meet the following allowable deviations for diameter:

  • for the diameter of up to 120 mm: + 0.6 and -1.3 mm;
  • for the diameter of over 120 mm: + 0.9 and -2 mm.

Milling serves for local removal of individual deep defects of a billet; sometimes the total peeling of the billet surface is performed on a milling machine. The special milling machines are used to mill the billets.

The milling machines are used to remove individual deep-seated defects of the billets of alloy steels except for some special hard steels such as tool steels. For example, it is not recommended to use such machines for a number of steel grades with the Brinell hardness number exceeding 241 that corresponds to the impression diameter of 3.9 mm.

During milling, the metal layer is removed to the depth of 10-15 mm; which makes an advantage in comparison to chipping. Sometimes, the complete removal of the metal layer from the billet surface is performed on milling machines; however, the best use of the milling machines is to eliminate defects.

Heat milling. This method involves repairing of the ingots (in hot state) on milling machines.

While conditioning the hot ingots, there is a number of advantages:

  • the ingot cooling after “stripping” (taking out of an ingot mold) is excluded;
  • the cracking danger is eliminated;
  • no annealing is required;
  • possible reject rate is reduced;
  • the working cycle of the ingot trimming is simplified and its total period is shortened;
  • the conditioning process productivity is 10-20 times higher;
  • the peeling costs are lower (10-40 times) in comparison to other methods;
  • availability of conditions to arrange a continuous process and totally mechanize and atomize it.

Basic methods for local (selective) conditioning of incoming billet surface

Local surface defects are eliminated by low-angle chipping with an air-operated chisel, grinding using an emery stone or burning-off by acetylene flame. The cut depth should not exceed 5% of the billet diameter; its flatness is determined by the maximum ratio between the width and the depth (the width should exceed the depth at least sixfold).

Chipping of local defects is performed using an air-operated hammer where the working tool is a chisel. Unlike usual metal cutting on lathes, planing and milling machines, where the cutter smoothly penetrates the metal, while chipping, the chisel penetrates the metal periodically, with every blow of hammer into the chisel end face. The frequency of blows of air-operated hammers of standard sizes is within 800-1900 blows per min.

The following factors affect the productivity of the chipping: standard size (power) and kind of the air-operated hammer, condition of the replaceable cutting tool (chisel), compression air pressure, mechanical properties and condition of the metal surface to be conditioned. The chipping with an air-operated chisel is a laborious and underproductive process. Today it is replaced by milling of separate local defects of ingots and billets on machines.

Equipment for cutting pipe billets to specified length

Cutting the incoming continuously cast or pipe billet into pieces with specified or multiple length is a critical procedure which determines the material consumption, laboriousness of the cutting process and quality of the billet end face.

The main characteristics that determine the quality of the end face of the cut-to-length billets include: a) out-of-roundness; b) misalignment of billet axis; c) surface roughness; d) absence of burrs.

The common methods of dividing are:

  • shear cutting;
  • breaking;
  • gas-flame and plasma cutting;
  • cutting by mechanical saws;
  • cutting by abrasive wheels and electromachining.

The shear cutting in the cold, warm and hot state, breaking of cold billets and cutting of cold and hot billets by saws, gas-flame and plasma torch are the most common methods used in pipe production.

A carbonaceous round billet with the maximum diameter of 140 mm is cut in the cold state by crank shears. This method can be used to cut billets with the maximum diameter of 180 mm, when they are preheated to the temperatures exceeding 650°C.

Cold (round) billets of carbon or alloy steel with the diameter of 150 ‑ 200 mm are broken on a hydraulic press after preliminary incising to the maximum depth of 20 mm along the chord with the length of 60 ‑ 90 mm. The incision is made using an acetylene or plasma torch.

Square and round billets of high alloy steel with the maximum diameter of 250 mm are cut in cold or hot state by saws. The incoming billet is cut into pieces with a specified or multiple length before such billet is loaded into the furnace. In the second variant, the final division of the billet is performed in the hot state prior to centering and piercing. The length of the cut-to-length billets is determined by the dimension of the finished pipe.

Modern methods and equipment for centering of incoming billets

Making a (centering) recess on the front face of the incoming billet (centering) will improve the catching conditions as well as reduce thickness variation of the front end due to precise setting of the piercing plug at the moment of touching the billet.

The main parameters of the quality of centering are wall thickness variation, shape and depth of the centering recess.

The shape of end face of the incoming billet, its out-of-roundness and alignment significantly influence the centering quality parameters. Even the incoming billet of highest quality such as pipe billet has the certain out-of-roundness.

Centering can be performed in cold state by drilling or firing out by acetylene flame, or pressing out of the hole with the maximum depth of 35 mm and maximum diameter of 30 mm by a hammer (preferably in hot state).

Technologies and modern equipment for heating of pipe billets

The heating process should comply with the main requirement that is the uniformity of the billet’s temperature prior to piercing (to its section and length). The nonuniformity of the billet’s temperature to its section is known to inevitably cause the wall thickness variation of hollow billet. The temperature nonuniformity to the billet length causes variation of wall thickness for the hollow billet length and makes the piercing process difficult. The heating mode affects the quality of the finished pipe, condition of the pipe surfaces, mechanical indexes and processing behavior.

Billets are preheated in furnace units before rolling:

  • ring (rotary-hearth furnace) furnaces;
  • sometimes, in sectional furnaces;
  • walking-beam furnaces;
  • walking-hearth furnaces.

Ring furnaces: the metal is heated during the hearth turning. The hearth turns at the angle of 320-340°. The hearth rotates intermittently. Billet placement spacing equals to one turn angle of the hearth. After the hearth is stopped, the tongs (of the loading and unloading machines) load/unload the billets into/from the furnace. The billet length determines the hearth loading type:

  • single-row loading;
  • two-row loading;
  • or staggered loading.

Sectional furnaces: here the heating is very intensive. The furnace can have up to 50 through-passage sections and a holding room. Between the sections, there are rollers transporting the long billets through the furnace while rotating them simultaneously. The heating is performed very quickly due to a high temperature (1400-1500°С) and continuous supply of heat from all directions. Disadvantages of sectional furnaces:

  • increased fuel consumption;
  • metal loss.

Walking-beam furnaces. Here, the width of the furnace hearth limits the length of heated pipes. Through-passage sectional or induction furnaces do not limit the pipe length. Induction furnaces have more advantages in terms of dimensions, scale formation and environmental conditions. Disadvantage of induction furnaces:

  • high investments into installation.

Peculiarities of piercing on screw-rolling mills

Choosing the piercing method type depends on the qualitative characteristics of the hollow billet. Its main parameters are presented below:

  • ratio between diameter and wall thickness, D/S
  • ratio between hollow billet length and hole diameter, L/d.

G. Pheiffer made the first attempt to define the expediency of application of two- or three-rolling mills as piercing mills.

Effect of a reeling mill on wall variation of the hollow billet. If it is neutral (pilger mill, push bench), a two-roll piercing mill is used because it allows obtaining the billets with lesser wall variation. If the reeling mill allows reducing the hollow billet wall variation (Assel mill) considerably, a three-roll piercing mill can be used.

Billet quality. If the quality of the billet is high, a two-rolling mill is used, if the quality of the billet is low, a three-rolling mill is used.

The hollow billets rolled on two- or three-rolling mills differ in wall variation level. The criterion for determining this parameter is in difference in strain-stress state during piercing.

Piercing of billets on press rolling mills

The hollow billet is pierced from a solid billet, mainly, by the equipment of screw-rolling mills. Due to high price of the rolled billet, the piercing on these mills is less efficient. It was impossible to use a round continuously cast billet instead of the rolled one because it was difficult to obtain a round incoming billet with the adequate surface quality in the 1970-1980s. It was caused by the specificity of metal crystallization in the cooling phase. Continuously cast square-profile billets have been used for manufacturing seamless steel pipes abroad for 10-15 years. Such billets are inexpensive and have good quality due to specificity of the casting and steel crystallization process. The use of continuously cast square-profile billets became possible after development and subsequent introduction of the press-roll piercing method.

Press-roll piercing used for manufacturing of the hollow billet from continuously cast square-profile billets was invented in Italy in 1970s. This process contains the pressing stage and rolling in a round groove.

The developers of this method define the following advantages:

  • using inexpensive continuously cast square-profile billets for manufacturing seamless pipes;
  • using heavy cast billets;
  • filling piercing which allows compressing the billets from all sides and obtaining the due quality of internal surface;
  • low power consumption for piercing in comparison with other technologies;
  • possibility of piercing the billets cast of high alloy chromium containing steels (with the chromium content of 5 and 13%), which are difficult to deform.

The disadvantages of this method are:

  • excessive sleeve wall variation that is corrected in the elongating mill;
  • difficulty of adjustment of the piercing process;
  • insignificant deformation at the coefficient of elongation μ < 1.2.

During piercing of a square billet by the press-roll method, the compressing stresses appear in metal. When the holding time is short (max. 1.2), it has positive effect on the process and qualitative characteristics of the hollow billet.

The experimental research abroad has shown that the plastic metal flow is directed not only along the billet but also across it during press-roll piercing.

The metal moves in the deformation zone, the square corners are drafted by the roll pass and when the plug enters the billet, a hole is formed in it. The external layers of metals move actively to the exit in the roll pass and then to the billet center. Near the internal surface of the billet, the metal flows plastically in the opposite direction. After piercing, the internal diameter of the hollow billet slightly exceeds that of the plug due to formation of a gap between the plug and the sleeve equal to 1 mm and more.

As noted above, the metal is actively deformed near the internal metal layers when square billets are pierced in the round pass. Moreover, the cast billet structure is actively processed, predominantly in the axial zone of the billet. The quantity of defects (cracks, flaws) inside the billet decreases considerably.

After the nature of the metal passage and distribution of the lengthening coefficient along the deformation zone in the press-roll piercing line had been investigated (a square continuously cast billet (the billet leg was 245 mm) was used for piercing), the diagram in the form of variation of the cross section S of the billet was constructed. When performing the test, the obtained hollow billet had the external diameter of 298 mm and the internal diameter of 146 mm.

At the initial stage of the process, the metal upsetting occurs before the plug nose, and the billet cross section area increases by 5.7%. Then this cross section decreases by 20.6%.

The actual deformation of the obtained hollow billet exceeds that of the incoming billet by 12.7%.

The results of metallography of the hollow billets received from the press-rolling mill demonstrate that the metal deformation is more significant on the billet surfaces, where the structure grains are smaller, while the structure at the billet center is coarse-grained. The hollow billets from this mill will be obtained with out-of-roundness of less than 15%.

The press-roll piercing line is considered to be high-performance equipment. The production, starting from piercing of the billet and finishing with the release of the finished pipe, can be carried out with single heating of the billet (before piercing) while increasing the speed of the subsequent rolling and reducing the time of transportation of the material from one operation to another.

The thick-walled sleeves with the D/S ratio of 4-5 are manufactured on the press-roll piercing lines. Then the wall is rolled off and bottom is pierced finally on the elongating mill.

Piercing on presses

The press piercing is used for manufacturing of the pipes using pressing method and for processing of the ingots or continuously cast billets on the lines equipped with pilger mills and push benches. As a rule, the press piercing is followed by rolling-off on the elongating mill.

When manufacturing the pipe product, the following kinds of press piercing are used:

  • piercing with a die in the container;
  • piercing mandrel (Erhard method);
  • piercing with a blind die.

Upon becoming the official distributer of pipe billets/slabs machines and equipment, our company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), carries out the following: finds the buyers of your products on the market, conducts technical and commercial negotiations with the customers regarding the supplies of your equipment, concludes contracts. Should a bidding take place, we will collect and prepare all the documents required for the participation, conclude all the necessary contracts for the supply of your equipment, as well as register the goods (machines) and conduct customs clearance procedures. We will also register a certificate of transaction (Passport of Deal) required for all foreign trade contracts in the foreign currency control department of the authorized Russian bank so that currency transaction could be effected. If required, our company will implement an equipment spacing project in order to integrate your equipment into the existing or newly built production plant.

We are convinced that our company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), will become your reliable, qualified and efficient partner & distributor in Russia.

We are always open for cooperation, so let’s move forward together!