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Custom Stainless Steel Pipe 304 Stainless Steel Pipe Hollow Stainless Steel Pipe Bright Stainless Steel Capillary
size
A. Nominal size: the nominal size stipulated in the standard, the
ideal size desired by users and manufacturers, and the order size
indicated in the contract.
B. Actual size: the actual size obtained in the production process,
which is usually greater than or less than the nominal size. This
phenomenon of greater or less than the nominal size is called
deviation.
C, meter weight: weight per meter =0.02466* wall thickness * (outer
diameter - wall thickness)
Deviation and tolerance
A. Deviation: in the production process, because the actual size is
difficult to meet the requirements of the nominal size, that is,
often greater than or less than the nominal size, so the standard
stipulates that there is A difference between the actual size and
the nominal size. A positive difference is called a positive bias,
and a negative difference is called a negative bias.
B. Tolerance: the absolute sum of positive and negative deviation
values specified in the standard is called tolerance, also called
"tolerance zone".
Deviation is directional, that is, "positive" or "negative";
Tolerances are non-directional, so it is wrong to call the value of
the deviation a "positive tolerance" or a "negative tolerance".
The length of delivery
Delivery length is also called customer required length or contract
length. The standard has the following provisions on delivery
length:
A, ordinary length (also known as irregular length) : where the
length is within the standard length range and there is no fixed
length requirements, are called ordinary length. For example,
structural pipe standards: hot rolled (extruded, expanded) steel
pipe 3000mm ~ 12000mm; Cold-drawn (rolled) steel pipe 2000mm ~
10500mm.
B. Fixed length: the fixed length shall be within the normal length
range and is a fixed length specified in the contract. But in
practice, it is impossible to cut absolute length, so the standard
stipulates the allowable positive deviation value for the length of
definite length.
The structural pipe standard is:
The yield of fixed length pipe decreases more than that of normal
length pipe, so it is reasonable for the manufacturer to raise the
price. Add price range each enterprise is not consistent, add price
10% or so on base price foundation commonly.
C. Length of multiples: the length of multiples shall be within the
normal length range, and the single length and the multiple of the
total length shall be indicated in the contract (e.g. 3000mm×3,
i.e. 3000mm 3x, with a total length of 9000mm). In practice, the
allowable positive deviation of 20mm should be added to the total
length, plus the incision allowance should be left for each single
ruler length. Take the structural pipe as an example, the specified
incision allowance: outer diameter ≤159mm is 5 ~ 10mm; Outer
diameter >159mm is 10 ~ 15mm.
If there is no length deviation and cutting allowance in the
standard, it shall be indicated in the contract through negotiation
between the supply and demand parties. Double ruler length is the
same as fixed ruler length, which will greatly reduce the yield of
production enterprises. Therefore, it is reasonable for the
production enterprises to raise the price, which is basically the
same as the fixed ruler length.
D. Range length: the range length is within the usual range. If the
user requires a fixed range length, it shall be indicated in the
contract.
For example, the length ranges from 3000 mm to 12000mm, and the
length ranges from 6000 mm to 8000mm or 8000mm to 10000mm.
It can be seen that the range length is more relaxed than fixed
length and multiple length, but it is much stricter than the usual
length, which will also reduce the yield of production enterprises.
Because this production enterprise puts forward add price is
reasonable, its add price range is in base price commonly add price
4% left and right sides.