We are interested in cooperation with the manufacturers of pipe billets, who are looking for an official and reliable distributor to supply 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. 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 for pipe billets in Russia, our marketing staff will carry out a market research in order to check the demand for pipe billets, will submit a market overview for pipe billets 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 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 or for various types of pipe billets 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 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 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 pipe billets. They will also provide necessary training and guidance for the customer’s personnel.
A source semi-finished product or a billet is used to produce seamless tubes. Up to 85% of the net cost of seamless tubes is the cost of the source material. The surface of the incoming billet should be of very high quality to ensure successful performance of process procedures traditionally used to produce seamless tubes.
To produce a complete range of hot rolled tubes using different methods, various types of the incoming material (billets) are used, for example, rolled billets (with round or square cross profile), ingots with round or multisided section, forged billets, continuously cast billets and centrifugally cast billets.
Rolled billets (with round cross profile) are used for piercing mill lines. Square profile billets are used for production in piercing press units.
Rolled billet with a diameter of 90-270 mm (round) is the most common billet type for today. Rolled billets may be subject to random surface quality control when arriving to the tube workshop if there are tube quality flaws detected due to steelmaking defects or rolling defects. Machined billets are preferred for production of boiler tubes and corrosion resistant tubes for special applications. This way, high quality of the tube surface is ensured. Additional structural analysis, microstructure and macrostructure checks are performed depending on application, and tube material grade.
Billets, in fact, are 3.5-12 m long beams as supplied to the workshop. Then they are cut to specific cut lengths, their front ends are centered.
The beams are shaped as follows:
Complete cutting of beams should be aimed at but, on the other hand, billets should have a set length to allow for production of tubes of certain sizes. In case of large orders for tubes, it is better to cut the feed to beams directly in the tube producing mill.
It is better to make a cup in the billet end center (perform centering) as follows:
It is done to decrease wall thickness variation at the front areas of shells to increase convenience of grip in the piercing mill. When the mandrel point enters the bullet, the length of the contact area is increased.
Ingots produced by the bottom pouring method are used in units equipped with a pilger mill. Tubes with medium and large diameters are produced in these units out of carbon steel and low alloy steel. Cast billets with uneven structure and a lot of ingot defects cause low plasticity of the material and high amount of tube defects. The reason to produce tubes of specified sizes and grades using ingots is their low cost in comparison to similar tubes produced out of rolled billets and billets of other types. Also, it is technically hard to roll billets with the diameter exceeding 270-300 mm. The maximum ingot diameter can reach 700 mm when producing tubes of maximum sizes.
Usage of ingots is a feature of lines equipped with a pilger mill. It is reasoned by specific distribution of deformation between piercing and rolling: a relatively low level of deformation during piercing of cast metal and a high reduction level of predeformed metal in the pilger mill.
The shape of the cross profile of the future ingot determines its quality. The shape depends on the choice of piercing equipment (mill or press).
Round profile ensures convenient grip of the ingot by the rolls of the piercing line. Multisided profile facilitates decrease of crack formation during crystallization (longitudinal crack formation). Ingot weight is 1-6 tons.
Ingots are prepared before rolling, namely, their surface is inspected and repaired. The repair is performed using notching and flame scarfing. Ingots used to produce critical duty tubes (for example, for boiler rooms) are drilled through, then metal with shrinkage porosity and a lot of non-metallic inclusions is removed from the central part.
Forged billets with round cross section are used to produce critical duty tubes with medium and large diameters, when it is impossible to manufacture rolled billets or it is unreasonable due to the small volume of the batch to be produced. Process characteristics of billets (forged and rolled) are generally the same.
Forged (whole) billets with a diameter of 150-270 mm (after turning) made of boiler steels, corrosion and heat resistant steels and titanium alloys are used to produce tubes in automatic rolling lines and rolling mills with 3 rolls. Forged billets with the outer diameter of 380-650 mm and internal diameter of 100-120 mm made of boiler steels are processed in lines equipped with pilger mills after drilling and turning.
Billets cast continuously out of carbon steel and alloy steels are usually processed in tube rolling plants and units equipped with pressing lines. Bottom poured ingots and rolled billets are usually processed in these units. The share of continuously cast metal is increasing, and tube rolling plants are using more of it. Technical and economic parameters of the casting procedure and finished tube products are improving, whereas power consumption is decreasing.
The following castings are used for tube production:
Round continuously cast billets are the least preferred in the tube rolling production. They are subject to crack formation during crystallization but can be used to make shells by piercing. Billet rectangular profiles are pre-rolled on the tube producing mill up to the diameter of 90-180 mm. Square profile billets are pierced on presses or press-roll mills.
Research in the area of rolling tubes made of whole round and hollow (continuously cast) billets shows the advantage of whole billets. They have a better metal consumption factor and higher quality characteristics for some tube types. The research on choosing the billet type for production of tube products is going on due to the developing quality characteristics of hollow billets.
Centrifugally cast shells are also used for different purposes:
Usage of centrifugally cast shells as tube billets has the following advantages:
Seamless tubes can be produced out of most metallic materials. On the scale of the tube industry, tubes are made of iron alloys (steel and cast iron), light metals, heavy non-ferrous metals, high-melting point metals and their alloys. Most steels are used to produce seamless tubes. Low carbon steels of grades 10-45, St5, St6 prevail in the grade range of steel hot rolled tubes production. Chemical composition of various steel (alloy steels and high alloy steels) classes is the most important factor in production of hot rolled tubes, namely, stainless, acid resistant, corrosion resistant and heat resistant tubes.
Semi-finished products made of quality grade steel are used for tube production. This steel differs from ordinary steels as it has low content of phosphorus and sulfuric harmful components. The appropriate quality of the tube steel is achieved also due to low content of dissolved nitrogen, oxygen, and hydrogen gases in it. Some tube steel grades are tested (for mechanical properties); their macrostructure and microstructure is controlled, in addition to the inspection of their chemical content.
Tubes used in the gas industry are made of steels with high carbon content, namely, casing and drilling pipe products. The same steel assortment is used to manufacture critical duty tube products of other types. Low carbon steels, for example, are used to manufacture steam boiler tubes.
Source semi-finished products used to produce seamless tubes are as follows:
The quality of the incoming tube billet is closely related to the quality properties of the future seamless tube. There are three directions of incoming billet production process enhancement known in our country and abroad:
Open-hearth furnaces, converters and electric arc furnaces are used to smelt tube steel.
The main defects of ingots:
There is a number of other quality related defects that occur during feeding steel into the mold and during steel ‘freezing’. Let us consider the main defects.
1) Axial porosity. There are small shrinkage cavities detectable in the fully killed steel ingot, in its axial part. They are called ‘axial porosity’.
Axial pores are not always welded when metal is rolled. This defect usually occurs when producing billets with big profile section due to low drafting degree. Axial porosity is determined in course of billet macrostructure inspection. If axial porosity is detected, which is unacceptable, this metal will not be used for production of critical duty parts.
Axial porosity has the following effects:
There is a direct dependence between axial porosity and coning. The more the coning, the higher the top layer hardening in comparison with the bottom layer. Ingots are made with a lower coning degree, for example, 2-4%. High coning makes it harder to roll ingots.
Axial porosity can be decreased by improving heating of the upper ingot section.
2) Skin ripple. It is the most common ingot surface defect.
This defect occurs because of:
The surface of the metal rising up in the mold is covered with an oxidation film when casting is made with a syphon. The film is formed as a result of air oxidization of steel components. Metal hardens under the film and together they form a skin. This skin absorbs all inclusions (non-metallic and slag). Signs of skin formation and growth are as follows:
The growing skin covers the metal surface and sticks to the mold walls. The metal moves upwards tearing and wrapping the skin. When skin oxidization products contact steel carbon, it leads to formation of inclusions (non-metallic) and gas blowholes. Tears and breaks occur when rolling rippled skin areas. The whole ingot surface can be covered with skin ripples when casting steels containing easily oxidizing elements (chrome, aluminum, titanium).
The surface of ingots covered with skin ripples should be conditioned before rolling. Abrasive discs are used as protection. Protection is applied by firing; chipping with pneumatic hammers and peeling on turning lathe benches might be also of help. But such conditioning methods slow down and complicate production procedures causing large metal losses. So, nowadays, a lot of methods are used to protect liquid phase metal surface against oxidization in the mold.
3) Transverse hot cracks. Outer cracks of transverse profile appear because the ingot gets stuck to the mold when crystallizing. If there are cavities or funnels in the mold or there is a gap between the mold and extension mold, the liquid metal fills these cavities and hardens there. The half-hardened ingot sticks in those cavities and it is already shorter due to shrinkage. The skin can tear up under the ingot weight as it is still thin.
Tight contact of the mold with the extension mold should be guaranteed and molds having bad (defected) walls should be disposed of in order to prevent the above mentioned defect.
4) Longitudinal hot cracks. If the skin of hardened metal is not strong enough, it can tear when the ingot is crystallizing, thus longitudinal hot cracks appear on the surface. Length of longitudinal cracks varies from 1 m and more, width varies from 1 to 3 mm. Сracks form in the following way: the skin of the hardened metal shrinks, the mold expands and a gap is formed between the mold and the ingot. Liquid metal accumulates in the walls of the hardened skin. Thin skin does not stand drafting and allows formation of longitudinal cracks usually in the corners of the ingot.
However, longitudinal cracks can form also at the sides of the ingot. It can occur due to incorrect distribution of liquid metal in the center in case of top casting. If metal flow hits the mold deviating from its axis, it washes out the skin of the hardened ingot. Skin can’t resist and breaks in thin places.
Longitudinal cracks are formed due to rise of steel temperature and high casting speed. Skin forms and grows slowly under these conditions. Mold shape also effects skin formation. Ingots cast in round molds tend to have more longitudinal cracks than ingots cast in molds of other shapes. The contact between the ingot and the mold is not very tight in round molds, so skin forms and grows slowly. The smallest amount of longitudinal cracks is formed on the ingots cast in rectangular molds with concaved and wavy edges.
Longitudinal hot cracks are prevented by:
5) Longitudinal cold cracks. External longitudinal cold cracks form on the edges of the ingot when it is cooled (below 600°С). It occurs if ingots are cooled very fast. The reason is thermal and phase stresses. To prevent formation of such cracks, ingots have to be cooled down slowly. And it is better to put them into heating wells while they are still hot.
Steels alloyed with chrome, manganese, silicon are more subject to form cold cracks. Cold cracks will occur if steel contains more than 0.4% carbon.
6) Skin blowholes. Blowholes form almost on the surface of the fully killed steel ingots, called skin blowholes.
Reasons for formation of such blowholes are as follows:
Skin blowholes can lead to formation of hair seams when rolling the metal. Hair seams are small, thin cracks.
7) Ingot rising and internal gas blowholes. It is a flaw of ingots made of fully killed steel. This defect is caused by a high content of hydrogen in steel. Excessive gas (hydrogen) is emitted when metal is crystallizing. It facilitates ‘rising’ of the metal in the mold and formation of blowholes in the ingot. Most frequently, it occurs in ingots made of silicon steel.
The demand to increase efficiency of metal production leads to development of new technologies in seamless tube production, i.e., continuously cast billets with round section and square, rectangular and multisided profile. These billets are either used directly in tube rolling units or previously rolled. Continuously cast billets are pre-rolled if there is a need to change the shape of a square continuously cast billet into a round billet in order to pierce it into a shell (on screw rolling lines). Sometimes this operation is performed to achieve necessary metal quality before piercing.
Continuously cast billets are cheaper and have relatively better quality characteristics in comparison with ingots cast normally. Continuous casting ensures minimum costs when producing billets with the diameter of 150-400 mm. But it is hard to readjust continuous casting units, so the tube rolling unit should perform the whole production program using billets of just a couple of standard sizes.
Dimensions of continuously cast billets:
Continuously cast billets can be used in any tube rolling line:
This way high tube quality and high output of good products exceeding the output when using ingots by 10-15% are achieved.
Nowadays, a process scheme has been established in the worldwide production practice which enhanced significantly the properties of incoming billets. Namely, the scheme is a combination of secondary refining of liquid metal and continuous casting (CC).
Secondary refining is an economically rational way to increase material quality.
All secondary refining operations are performed in a ladle, namely:
Secondary refining has certain advantages in comparison with refining of steel in the furnace. These procedures performed in steel melting furnaces significantly increase the melting time and decrease technical and economic performance. Due to the modern secondary refining methods, customary specialization of steel melting units in terms of melted steel grades has fully changed. The technological process of quality steel melting is more and more reducing to obtaining liquid product and further removal of phosphorus and carbon, sometimes sulphur, to the set limits (in the ladle).
Performance of steel melting lines dramatically increases with the use of this technology.
Technological capabilities of steel melting lines for new steel grades have increased due to secondary refining. Previously, production of such steels considered to be impossible. Particularly, steels with low content of carbon and sulphur, low limits for alloying elements, steels for tubes operated under negative temperature and pressure belong to this group.
Metallurgical complexes are using more such types of secondary refining treatment as metal purging with inert gases, powdered (refining and carbonizing) materials; treatment with synthetic slags and slag-forming mixtures; vacuuming and electromagnetic steel agitation.
Worldwide operation experience of blast furnaces shows that it is almost impossible to produce cast iron with stable chemical composition corresponding to the conditions of its processing in basic oxygen converters. Therefore, to achieve the required steel quality, it is necessary to perform external desulphurization of cast iron, which is being more commonly used in plants, along with secondary refining of steel in steel casting ladles.
Chemical composition of steel, its purpose and types of further treatment determine the choice of methods to increase steel quality. Production conditions and requirements for the finished product play a significant role too. Main requirements are as follows:
Harmful impurities significantly decreasing all useful properties of steel are sulphur and phosphorus.
The result of sulphur content reduction in steel is as follows:
Analysis of the change of tube steel impact viscosity shows that significant enhancement of these characteristics occurs if S < 0.015 %. It was established that increased sulphur amount (more than 0.02%) causes increase of slab surface defects.
Decrease of sulphur content is especially important in metal production where fine metal drawing is needed or if cast ingot weight is large.
Sulphur amount can be decreased by reducing its content in the source product, i.e. cast iron. Desulphurization of steel in converters, tandem furnaces, and electric furnaces of high capacity will not allow to do this. Nowadays, secondary refining is one of the successful process types of steel fine desulphurization.
The technology of liquid steel desulphurization in the ladle is commonly used worldwide. Desulphurizers in powder form (calcium carbide, silicocalcium, magnesium, mix of fluor spat with lime and etc.) are blown in the ladle through the tuyere with the flow of inert gas. After this operation, the content of sulphur in metal is less than 0.006%. Efficiency of this method can be increased 1.5-2 times if refractories preventing additional ingress of oxygen into metal are used when lining ladles.
Implementation of the process of blowing powdered desulphurizers is related to creation of absolutely new equipment for powder and powder mix preparation, transportation and dosing dust and gas mixes providing flexible control of dust and gas flow density and oxidization potential of gaseous mixes.
Distinction of this method of secondary metal refining is its unambiguous direction in relation to creation of complex units that provide not only for metal refining of harmful impurities but also adjusting its chemical composition, temperature, creating conditions for removal of non-metallic inclusions, obtaining the necessary microstructure and macrostructure. All these operations make it possible to achieve the required mechanical properties and service characteristics of metal products.
Decrease of content of phosphorus, which is usually undesirable in steel, is usually performed in steel melting furnaces. Secondary dephosphorization of cast iron and steel is used rarely as the steel production process comprises oxidization and there is no problem to perform dephosphorization in a furnace or a converter. Presence of oxygen and hydrogen in steel affects its properties. Their increased content causes higher fragility and aging tendency (due to large amounts of oxide inclusions), formation of flakes, center porosity, surface blowholes, plasticity decrease and fatigue strength.
Nitrogen is not always harmful in steel, it can be even used as an alloying component. It facilitates strengthening of some structural metal grades. Nitrogen content in steel should be low in the following cases: production of sheet low alloy metal for further fine drawing, for melting of tube and structural metal grades to be used in severe cold conditions and/or under high pressure.
Vacuum blowing with inert gas is the most efficient method to decrease the content of these gases in metal.
Chemical composition and structure of metal compounds with metalloids (non-metal inclusions) in steel also have an impact on mechanical metal properties, ingot composition heterogeneity, tendency to cracking, welding ability. Grain size and even location of non-metallic inclusions are controlled by adding special modifiers to steel. They are added after production of steel, during secondary refining.
We decrease the degree of pollution with non-metallic inclusions by protecting steel from secondary oxidization during casting. Such protection can be provided by argon, slags, thermal insulating mixes. Also protection can be achieved with casting ‘by level’.
Quality of ingots and continuously cast billets is enhanced significantly when treated under pressure. High quality (high alloy) steel billet for further production of tubes using pressing can be obtained as a result of forging ingots with profiled outer surface, then turning the outer surface and hole drilling. But the efficiency of the process is decreased due to the relatively low coefficient of metal usage and high labour intensity. Schemes of rotational and radial forging can’t be considered as efficient because of the stated reasons. Planetary rolling, a method used abroad, which can be combined with continuous casting (for example, in a casting and rolling complex), is distinguished by complexity of the used equipment and relatively low performance.
A new deforming method has been developed, namely, radial-displacement rolling. It is used to produce tube billets too.
This method is based on screw rolling under a big (more than 15°) supply angle, high force drafting (single and total) using two-roll or three-roll stands.
Conditions for compaction and intensive deformation of the metal in the deformation center are created in radial-displacement mills in comparison to screw rolling mills, where conditions for opening of the central area are usually created. Possible variations of intensity of shape changing, internal stresses and deformations of metal are used for this purpose. Changing of the main controlling factors is used to achieve these conditions, namely, spatial orientation of working roll location and deformation center geometry.
Experience of operating mills with a big supply angle shows that it is possible to achieve compacting of the rolled billet axial area. It is known that the scheme of rolling in a three-roll mill, where a guiding tool is not used, provides a higher flexibility of the mill. The produced rod size is determined by the arrangement of rolls. They are brought closer or opened wider to provide necessary caliber. Absence of the guiding tool brings down power consumption and prevents metal adhesion. This scheme allows to ensure high drawing performance in course of one run, if specially calibrated rolls are used.
A billet is drafted by its diameter followed by intensive compaction of metal in the deformation center while moving by a set path with big lifting angle in narrowing caliber created by three operating rolls.
Upon becoming the official distributer of pipe billets, 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 (pipe billets) 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!