Seamless steel pipe terminology analysis of external dimensions and delivery status
Date:2019-05-13 View(s):1117 Tag:Seamless steel pipe terminology analysis of external dimensions and delivery status
The China Seamless Pipe Network website was informed that with the deepening of the supply side reform, the capacity to be effectively promoted, as a small variety downstream of the steel industry - seamless pipe is facing industry reshuffle. On the one hand, the profit level has increased in the past two years, and the newly added capacity is obvious. On the other hand, the elimination rate of SMEs in the industry is accelerating, and the new capacity increases the supply pressure of local billets.
With more new seamless pipe production lines put into operation in 2018-2019, the supply pressure of pipe blanks continues to increase. The total output of seamless pipes in 2018 is 2,694,600 tons, of which 48% is the production of green compacts, of which 30% are produced. From Shandong, then according to Zhuo Chuang estimates, Shandong tube billet steel demand is about 8 million tons, but tube billet steel Shandong self-production capacity of nearly 6.8 million tons, there is still a 1.2 million tons demand gap.
Then we compare the price of resources around Shandong to determine which areas of resources may flow into Shandong in the future.
From the price point of view, Jiangsu tube billet price is higher than Tianjin price, and is the normal state. From the perspective of freight, Tianjin to Linyi freight 120-130 yuan / ton. The cost of Tangshan to Linyi is about 170 yuan/ton. The freight rate from Jiangsu to Linyi is around RMB 100/ton. If the price of tube billet in Jiangsu is 20-50 yuan/ton higher than that in Tianjin, there is still an advantage to enter the Shandong market. Exceeding, Tianjin tube billet is more dominant.
All in all, there is a certain demand gap in Shandong's carbon steel billet steel in the future, which will lead the Shandong tube billet steel production enterprises to focus on, and will also attract foreign resources inflow. In addition, this also means that the price of tube billet steel will be stronger in 2019, and the cost of billeting enterprises will be a big problem that plagues corporate profits.
Manufacturers often ask us some technical terms when purchasing seamless steel pipes.
1. Nominal size and actual size
A. Nominal size: is the nominal size specified in the standard, is the size that the user and the company want, and is the size indicated in the contract.
B. Actual size: It is the actual size obtained during the production process. The size is often larger or smaller than the nominal size. This phenomenon of greater or lesser is called deviation.
2. Deviation and tolerance
A. Deviation: A difference is allowed between the actual size and the nominal size. The difference is positive positive difference and the negative negative negative difference.
B. Tolerance: The sum of the absolute values of positive and negative deviation values specified in the standard is called tolerance. The tolerance is non-directional.
Seamless steel pipe terminology analysis of external dimensions and delivery status
3. Delivery length
The length of delivery is also known as the length of the user request and the length of the contract.
A. Normal length: Also known as non-fixed length. Where the length is within the length specified by the standard and there is no fixed length requirement, it is called the normal length.
Structural pipe standards stipulate:
Hot rolling (extrusion, expansion) steel pipe:
Cold rolled (drawn) steel pipe:
B. Fixed length: usually within the normal length range, which is a fixed length dimension required in the contract, but the actual length is impossible to cut out; therefore, the standard specifies that the length of the fixed length allows a positive deviation (only More or less).
Structural pipe standard: The price increase requirement is generally about 10% of the base price.
C. Double-length length: The length of the double-length should be within the normal range. The length of the single-length ruler and the multiple of the total length should be indicated in the contract (for example, 3000X3, which is 3 times of 3000mm, which is 9000mm). In practice, the allowable positive deviation of 20 mm should be added to the total length, plus the remaining allowance for each single-length length. (10%)
For example, the structural tube: outer diameter ≤ 159mm, 5~10mm outer diameter > 159mm,
D. Range length: Within the usual range, the user requires one of the fixed range lengths. Must be stated in the contract. (4%)
Example: usually the length is
Range length is
Seamless steel pipe terminology analysis of external dimensions and delivery status
4. Uneven wall thickness
In order to control the uniformity of the wall thickness, the allowable index of unevenness is specified in some steel pipe standards, and the general regulation does not exceed 80% of the wall thickness tolerance. (both sides negotiate)
5. Ellipticity
The difference between the maximum outer diameter and the minimum outer diameter is the ellipticity. In order to control the ellipticity, some steel pipe standards specify the allowable index of ellipticity. It is specified that 80% of the outer diameter tolerance is not exceeded (negotiated by both parties).
6. Curvature
The steel pipe is curved in the length direction, and its curve is called the degree of curvature.
A. Local bending (1m) H chord height
B. Total total bending H chord height max L total length (100%)
7. Dimensional deviation
The size is out of tolerance or the size exceeds the standard tolerance. (mainly refers to the outer diameter and wall thickness of the steel pipe)
China Seamless Pipe Network website learned: delivery status:
The state of delivery refers to the state of the final plastic deformation of the product or the final heat treatment. general
It is said to be hot rolled or cold rolled (drawn) or manufactured in a state where it is not subjected to heat treatment. After heat
Handling the heat treatment state of the delivery, or weighing it according to the type of heat treatment (normalization), adjustment
Quality, solid solution, annealing state.
