General Terms In The Technical Requirements Of Steel Pipes

When shopping for steel pipe, you may often come across some confusing jargon. So, what do these terms mean? What are the common terms for steel pipes? The following is a detailed introduction for you by Union Steel Industry.

1. Delivery Status

Final plastic deformation or final heat treatment of the delivered product. Generally, delivery without heat treatment is called hot-rolled or cold-drawn (rolled) state or manufacturing state; delivery after heat treatment is called heat treatment state, or normalizing treatment according to the type of heat treatment

(Normalizing), quenched and tempered, solid solution, annealed state. When ordering, the delivery status must be stated in the contract.

2. Delivery by Actual Weight or Theoretical Weight

Actual weight - at the time of delivery, the weight of the product is delivered according to the weighed (weighted) weight;

Theoretical weight - when delivered, the weight of the product is calculated according to the nominal size of the steel.

3. Guarantee Conditions

Inspection according to the provisions of the current standards and guaranteeing compliance with the standards are called guarantee conditions. Guarantee conditions are further divided into:

- Basic Guarantee Conditions (also known as Required Conditions). Regardless of whether the customer specifies it in the contract. Inspections shall be carried out in accordance with the standards to ensure that the inspection results meet the standards. Such as chemical composition, mechanical properties, dimensional deviation, surface quality and technical performance tests such as flaw detection, hydraulic test or flattening or flaring are all necessary conditions.

- Agreement guarantee conditions: In addition to the basic guarantee conditions in the standard, there are also "according to the requirements of the buyer, negotiated by both parties and specified in the contract" or "when required by the buyer"..., which should be noted in the contract "; Some customers put forward stricter requirements on the basic guarantee conditions in the standard (such as composition, mechanical properties, dimensional deviation, etc.) or increased inspection items (such as steel pipe ovality, uneven wall thickness, etc.). The above terms and requirements It should be determined through negotiation between the supplier and the buyer when ordering, and a supply technology agreement should be signed and specified in the contract. Therefore, these conditions are also called agreement guarantee conditions.

4. Batch

"Batch" in this standard refers to an inspection unit, that is, an inspection lot. If grouped by delivery unit, it is called a delivery batch. When the delivery batch is large, one delivery batch can contain multiple inspection batches; when the delivery batch is small, one inspection batch can be divided into multiple delivery batches.

The composition of a "batch" usually has the following requirements (see relevant standards for details):

- Each batch shall consist of steel pipes of the same brand (steel grade), same furnace (tank) number or the same main furnace number, same specification, and same heat treatment system (furnace).

- For high-quality carbon steel structural pipes and fluid pipes, they can be composed of steel pipes of the same grade, same specification, and same heat treatment system (furnace) in different furnaces (tanks).

- Each batch of welded steel pipes shall consist of steel pipes of the same designation (steel grade) and same specification.

5. Portrait and Landscape

In the standard, the longitudinal direction refers to the direction parallel to the processing direction (that is, along the processing direction); the transverse direction refers to the direction perpendicular to the processing direction (the processing direction is the steel pipe direction).

In impact energy tests, the fracture of longitudinal specimens is perpendicular to the machine direction. Therefore, it is called transverse fracture; the fracture of transverse specimen is called longitudinal fracture because it is parallel to the processing direction.