凡产品尺寸（长或宽）在标准范围内，且不要求固定尺寸的称为不确定。不定长度也称为正常长度。按不定长度交货的金属材料，可在规定的长度范围内交货。例如，普通圆钢的长度不超过25 mm，长度在4-10 m之间的圆钢可以交货。
1. Range size of steel
It is an effective measure to save material to specify the range size of steel. Range sizing means that the length or the length multiplied by the width is not less than a certain size, or the length and length multiplied by width are delivered within
the size range from how many to how many. The production unit can supply products according to the size requirements.
2. Indeterminate (usually length)
Where the product size (length or width), within the scope of the standard, and does not require fixed size is called indeterminate. The indefinite length is also called the normal length. The metal materials delivered according to the indefinite length
can be delivered within the specified length range. For example, if the length of ordinary round steel not more than 25 mm is 4-10 m, the round steel with the length within this range can be delivered.
According to the order requirements cut into fixed size is called fixed length. When delivery is made according to the fixed length, the delivered metal materials must have the length specified by the demander in the order contract. For
example, if it is specified in the contract that the delivery should be made according to the fixed length of 5 m, the delivered materials must be 5 m long, and those shorter than 5 m or longer than 5 m are unqualified. But in fact, the delivery can not
be 5m long, so it is stipulated that positive deviation is allowed, but negative deviation is not allowed.
4. Multiple ruler
According to the order requirements of the fixed size cut into a full multiple is called a double ruler. In case of
delivery according to the multiple length, the length of the metal material delivered must be the integral multiple of the length (called single scale) specified by the demander in the order contract (with additional saw). For example, if the buyer requires
a single length of 2m in the order contract, then the length is 4m when it is cut into double ruler and 6m when it is cut into three times. One or two saws are added respectively.
The sawing amount is specified in the standard. When delivery, only
positive deviation is allowed, and negative deviation is not allowed.