Datong Hydraulic

 E355 Cold Drawn Seamless Tube Production Process and Heat Treatment​ ​1. Billet Preparation​: ​Material Selection: High-quality carbon steel, alloy steel, or stainless steel billets are sourced.  ​Cleaning: Billets are cleaned to remove surface oxides or contaminants. ​2. Heating​: Billets are heated in a furnace to 1100–1300°C (depending on material) for plasticity and machinability. ​3. Piercing​: A rotary piercer or cross-roll piercer is used to create a hollow tube blank (mandrel bar) at high temperatures. This step forms the initial tube shape. ​4. Hot Rolling (Pilger Rolling)​​ :The hollow tube is elongated and reduced in diameter via a pilger mill, improving dimensional accuracy and surface finish. ​5. Cold Drawing ​ ​Process: The tube is drawn through a die and mandrel at room temperature using a cold drawing machine. Multiple passes may be required to achieve final dimensions. ​Lubrication: Lubricants (e.g., soap or emulsion) reduce friction and prevent galling. ​Res...

  DIN 2391 ST35 NBK Seamless Tubes come under AISI, DIN, EN, GB and other international standard specifications. they range from 4mm to 219mm in outer diameter with wall thicknesses ranging from 0.5mm to 20mm.  ST35 Seamless tubes are frequently used for high heat and pressure applications in oil and gas( high pressure oil pipes ) petrochemical, hydraulic cylinders & pneumatic cylinder,mechanical and Automotive engineering petroleum, and other industries. They come in various sizes and forms, including round, square, and U-shaped. Furthermore, these stainless steel tubes’ strength and corrosion resistance are well known. They are frequently produced with a seamless finish and can be used in many different sectors. ST35 is one of the best choices among the various types of steel tubes for low-cost, low-corrosion pipes. It has muscular tensile and yield strength and may be formed into round, square, or oval tubes. These stainless steel tubes’ ability to be welded without an...

  High precision cold drawn tube  surface roughness Ra ≤ 0.8μm, diameter size accuracy can reach H9 ~ H10, only to ensure that after honing to H7 ~ H8 bore size and Ra ≤ 0.2μm of the internal surface roughness requirements. In addition to the honing machine equipment precision, the cold drawn tube surface quality is another key point, cold drawn tube internal surface defects by the domestic A factory measured data classification, there are three kinds of main  honing pipe  surface roughness. 1. Pitting: After rough drawing, the surface can be found by many pits-like defects, such defects will not seriously affect the smoothness of the cylinder bore, for the cylinder is a waste. 2. Scratch: Scratch defects are cold drawn, generally along the axis of a steel pipe along the direction of the scratches, there must be more than the depth of the scratches honing margin, it is possible to grind away such defects, processing a qualified  cylinder . 3. Not round: Cold dra...

 The hydraulic steel tube is cylinder-like shaped tubing device that when attach to hydraulic systems, allow for the passage of fluids within and among components. The tube standard specifies dimensions for cold drawn finishing and ​seamless precision steel tubes. Cold drawn process provides the tube with close dimensional tolerances, increase material strength and enhanced machinability. Therefore, hydraulic tubes are suitable in high performance piping system application. Hydraulic steel tube is basically divided into the hydraulic system with fluid pipe and oil cylinder, also known as honing tube, and cold drawn or cold rolled precision seamless steel pipe also contains hydraulic tube. Hydraulic pipe after finishing, no oxidation bright heat treatment of raw materials (NBK), nondestructive testing, steel pipe inner hole through high pressure washing, pickling, block on both ends of the steel tube inside and outside wall with anti-rust oil antirust proce...

  Cold drawing (rolling) steel tube: round pipe blank → heating → piercing → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → blank pipe → heat treatment → straightening → hydrostatic test (flaw detection) → marking → warehousing. What is a  cold drawing steel tube ? Hot-rolled steel pipe is made of continuous casting slab or initial rolling slab as raw material, which is heated by walking-beam heating furnace, descaled by high-pressure water, and then entered into roughing mill. The roughed material is cut into head and tail, then entered into finishing mill, and then rolled by computer control. After final rolling, it is cooled by laminar flow and coiled by coiler to become straight hair coil. The head and tail of straight hair curls are often tongue-shaped and fishtail-shaped, and the accuracy of thickness and width is poor. The edges often have defects such as wave shape, folded edge and tower shape. OUR HOT PRODUCTS: Skiv...

  Cold drawing is the pulling of a hot rolled steel bar through a die that is slightly smaller in size.  So how is cold drawn steel made?  The process path that   Datong Hydraulic   uses consists of first shot blasting the hot rolled bar, then cold drawing it through the die, then rotary (roll) straightening, and finally cutting to length. Shot blasting: This initial operation will clean the surface of the hot rolled bar, essentially removing all scale and rust.  This operation also creates a bar surface which will help carry the drawing lubricant into the die. Cold drawing: The main operation, which actually produces the  cold drawn steel tube .  We use a heavy frame drawn bench which can draw out over 40′ long finished cold drawn bars.  The die itself is mounted securely so as not to move during operation.  A pusher mechanism will grab the bar and advance the first 12″ of the bar through the die.  Next a buggy carriage will g...

  Cold rolling refers to the process of hot rolling sheet at room temperature. Although the process of rolling can also raise the temperature of the plate, it is still considered as Cold Rolling. Cold rolling by hot rolling after continuous cold deformation, produce poor mechanical properties and higher hardness, require annealing to restore its mechanical properties.  Cold Rolling product refers to the rolling of flat rolled sheet and bars. Cold rolling is processed further in cold reduction mills at room temperature, where the material is cooled followed by annealing and tempers rolling. This process will improves the surface finish and holds tighter tolerances while cannot reduce the thickness of a work piece. Cold Rolled steel coils and sheets are generally used to make products that do not require bending or simple deformation and stretchi...

Heat treatment of  seamless steel tubes  is a process to improve the properties of metal materials and their products. Depending on the use, the material and its workpiece are heated to the appropriate temperature, insulated, and then cooled in different ways to alter the internal structure to achieve the desired performance. Heat treatment of seamless steel tubes is generally divided into annealing, normalizing, quenching, tempering, failure, chemical heat treatment and vacuum heat treatment. By heat treatment, the efficiency or life of the steel can be improved, and in some cases, more expensive special materials can be used instead of cheaper ordinary metal materials. The basic heat treatment methods of seamless steel tubes mainly include the following four forms: 1. Annealing Annealing is a process in which a seamless steel tube is heated to a slightly higher or lower critical temperature for a period of time (ie, heat preservation) and then slowly cooled. Common annealing...