The researchers of the 20th century, 80 years ago appeared inclined rolling mill pressure calculation formula
The analysis, that can be divided into the following types:
① borrow rolling and pressure plate unit formula, such as mining in the Markov formula, Robert formulas.
② According to the skew rolling carbon steel seamless pipe itself deformation characteristics, with plastic mechanics Engineering method (analytical method) to push
Theory derived type, such as Braginski formula.
③ with slip line derived theoretical formula.
④ empirical formula. Researchers borrow rolling and rotary piercing approximate calculation formula unit pressure
Methods for indepth analysis and research that is calculated using rolling and cross rolling problem seems to be unreasonable, however, if the skew rolling as a continuous rolling and the process is still justified. By deforming
Launched the crosssectional area, indicating the equivalent of sharing a diagonal rolling within processing rollers (head or mandrel) of
Multi base of two rollers rolling and rolling form and therefore rotary piercing unit pressure calculation formula is borrowed longitudinal rolling
Allow and reasonable. But in the application, pay attention to the vertical strip rolling geometric formulas and deformation parameters
Correctly characterize diagonal rolling into the characteristics of geometric distortion parameters. There will be some of the vertical rolling theory research
Further extended to the study conclusions diagonal rolling calculation, discussed how to determine the impact of external friction coefficient, the stress state
State coefficient and the deformation resistance.
Flying .4.3 rolling and basic research
Type in the hole in the vertical rolling process carbon steel seamless pipe is perforated (push piercing), elongation (automatic rolling, even
Rolling, Pilger, pipe jacking), sizing, reducing (tension reducing, micro tension reducing), most of which
Number two rolls and three rolls. Rolling and the main emphasis on basic research rolling tension reducing management theory and the theory side
Surface, which is due to their plastic deformation theory, geometry and kinematics, pass design and stress analysis
Representative.
(1) rolling management theory. Theoretical study of the vertical rolling pipe rolling tube machine is mainly reflected in the upper floating mandrel
And retained mandrel rolling process of the study. Through research that: carbon steel seamless pipe rolling surface and the largest in the neutral
The pressure side do not overlap; unit laterally maximum pressure gradually decreases linearly distributed, max
Near the midpoint of the arc of contact; hole at the top of the forward slip zone length maximum, with the horizontal coordinate increases shrinkage forward slip zone
Short; rolling process along the width of the distribution of the neutral line traces approximate elliptic curve; friction factor in the rolling direction
Direction and the width direction are changing, the friction factor is greater than the outlet side of the inlet side; feelings in the same conditions
Case, retained mandrel rolling force 30 percent smaller than the floating mandrel, while rolling torque about 20%.
At the same time, the application of the principle of minimum energy variational method, strip element method for solving the metal rolling pipe deformation zone
Threedimensional flow rate, strain rate, stress distribution, the rolling friction force distribution unit and the pressure distribution.
(2) reducing tension theory. Our manufacturing ∮ 76 garbage garbage, ∮ 108 garbage garbage tension reducing test sets
Prototype in the early 1970s put into trial production for the domestic tension reducing design and production process to explore
Experience. Since the design of process parameters not correctly calculated, resulting in two sets of students in the test unit
Production, often occurring carbon steel seamless pipe and equipment to pull off an accident damaged parts. The main force parameters for experiments
Determination, a detailed analysis of the cause of the accident that, ∮ 76 garbage garbage, ∮ 108 garbage garbage stretch reducing mill happen carbon steel seamless pipe
Pull off because of reducing the total amount of the original design, the total amount of reduction process parameters such as the wall is too high, resulting in tension coefficient over
High individual rack tension coefficient has reached 0.94, while the measured maximum rolling moment is the device design strength
Several times, so the future stretch reducing mill should be designed as a computer stand rolling torque and transmission intensity
Degree basis.
In the early 20th century, in the early 1970s, in ∮ 76 garbage garbage tension reducing pilot study on the unit
Tension, reducing the amount of a single frame and its allocation, female design right tension reducing carbon steel seamless pipe within the sixparty influence. Through years of repeated experiments and practice, has been basically understand the factors that influence the Hexagon, succeeded in finding
A number of ways to overcome. Specifically, stretch reducing mill rack not too little; S / D <0.1 for carbon steel seamless pipe,
Reducing the amount of the largest single aircraft should be limited to 8.2% or less; 0.10 ≤ S / D ≤ 0.135 for carbon steel seamless pipe, the largest single
Reducing the amount of aircraft should be limited to 7.5% or less; landing racks should be increased, Masahiro exhibition pass can be 5
Aircraft landing, zero and negative width spread wide exhibition pass can be used four landing; rack reducing the amount of work rises later,
Should gradually fall, the specific pro rata allocation method to allocate; S / D <0.10 for carbon steel seamless pipe, should be used Zhengkuan
Exhibition pass design; 0.10 ≤ S / D ≤ 0.135 for carbon steel seamless pipe, should be zerowidth spread pass design; S / D>
0.135 of carbon steel seamless pipe, should pass design using negative width spread.
By studying the 1980s stretch reducing pipe wall thickness distribution pattern thickening segment, as well as a variety of working
Arts influence factors on the law, the thickness distribution curve fitting shape, more accurate results can be expressed
Tension coefficient, reducing the amount of transmission form, frame spacing, thickness coefficient, the shortage of pipe wall thickness and other processes
Parameters on the stretch reducing pipe wall thickness distribution patterns affecting segment mathematical model, using this mathematical model
Designed to produce a thin, middle thick ends, waste pipe ends tapered rolling mandrel. With this core
Rod ends can produce prewall thinning carbon steel seamless pipe.
1.5 of carbon steel seamless pipe production development process
Founding of New China, China had only one simple drawing furnace carbon steel seamless pipe welding machines and more than 10 minutes
Scattered in several cities trombone molding, artificial hand soldering or simple mechanical exhaust pipe welding machine.
China's first pipe factory was built in 1921 in Shanghai Rongtai pipe plant. Later, after another in Shanghai
Built a production bedstead tubes, square shed, conduit and plumbing pipe factory, etc., the liberation of the city from Shanghai
More than 10 pipe factory, only a few hundred tons of annual production. In addition, in Shanghai there are several drawing machine, the earliest
Was built in the late 1930s Limao Chang Machinery Factory (1939 changed its name to Wing Tai Iron Works,
1941 was renamed the Wing Tai drawing plant), fitted with a screwtype drawing machine sets. There was built in 1940
The Sanhe pipe plant, equipped with a desk chain drawing machine. At that time, because China has not yet raw carbon steel seamless pipe
Production plant, so these drawing machine, mainly imported tube feeding tube, or scrapping old tube restructuring process
(Big piecemeal, small change big, thick changed thin, short and long pull).
Now China is carbon steel seamless pipe producing countries, production ranks first in the world. Review of carbon steel seamless pipe production
Development process can be divided into the basic cornerstone of the 1950s period of 60 to 70 years of production technology
After 80 years of popularity and improvement and development of these three stages.
