-
About us
Tianjin lefin Industrial
TIANJIN LEFIN STEEL GROUP containing Tianjin lefin Industrial Co.,Ltd. 、Tianjin lefin steel import & export Co.,Ltd and Tianjin Shengqifeng International Trading Co., Ltd. -
Products
Steel Pipe Processing
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard -
-
Service Capability
Guarantee Quality
Our steel pipes are suitable for oil, natural gas, shipbuilding, chemical industry, water conservancy, electrical, steel structure, construction and other related fields.
Is Modification And Drawing A Processing Technique For Seamless Pipes
Release time：
2025-08-28
"Modification and drawing" is an important subsequent processing procedure in the manufacturing process of seamless tubes (SMLS).
1. SMLS (Seamless Pipe) - Base material
• Meaning:
SMLS is the abbreviation of "Seamless Steel Pipe" in English. It refers to steel pipes without welds that are manufactured mainly through methods such as hot rolling, extrusion or piercing.
• Core:
The core of the SMLS process is "manufacturing the tube" itself. The tubes produced at this stage are usually referred to as "hot-rolled tubes" or "tube billets", and their dimensional tolerances, surface finish and mechanical properties may not yet meet the requirements of some high-end applications.
2. "Cold Drawing" - Subsequent finishing process
• Meaning:
"Modified drawing" is the common name for the "cold drawing" process in China, especially in some regions or within certain industries. It is carried out at room temperature by drawing the already made SMLS hot-rolled tube billets through a die to cause plastic deformation.
• Core:
The core of the cold drawing process is "the fine processing and improvement of the existing SMLS tubes".
• Objective:
◦ Reduce size:
Achieve a smaller and more precise outer diameter and wall thickness.
◦ Improve accuracy:
Achieve dimensional tolerances far superior to those of hot-rolled tubes.
◦ Improve the surface:
Achieve a very smooth and shiny surface.
◦ Enhance performance:
Through the "work hardening" effect, improve the mechanical properties such as strength and hardness of steel pipes.
3.The relationship between the two: a complete process
SMLS (Hot-rolled tube billet) → Cold drawing (" modified drawing ") → Cold-drawn seamless tube (final product)
You can imagine it as:
• SMLS hot rolling:
It's like casting a rough blank of a sword with a mold (having the shape of a sword but being very rough).
• Cold drawing (" modified drawing ") :
Just like a craftsman polishing, quenching and precisely sharpening the rough blade of this sword, eventually turning it into a sharp and accurate precious sword.
4.Summary and comparison
It is the base material and foundation of cold-drawn tubes, and it is a deep-processed and upgraded product of SMLS tubes:
| Feature | SMLS (hot-rolled seamless tube) | Modified drawing /Cold-drawn seamless tube |
| Process properties | Main manufacturing process | Subsequent fine processing technology |
| Raw material | Steel billets, Steel ingots | SMLS hot-rolled tube billets |
| Processing temperature: | High temperature | Normal temperature (cold state) |
| Product features | Large dimensional tolerance, oxide scale on the surface, relatively low strength, | extremely high dimensional accuracy, smooth surface, high strength and hardness |
| Relations | It is the base material and foundation of cold-drawn tubes | It is a deep-processed and upgraded product of SMLS tubes |
5.Conclusion
"Modification drawing" (cold drawing) is not a process for manufacturing SMLS tubes, but rather a process for deep processing SMLS tubes. After the "modification and drawing" treatment, the basic material of the steel pipe remains seamless (SMLS), but its dimensional accuracy, surface quality and mechanical properties have all been greatly improved.
You can say: "Modified drawing Pipe is a kind of high-precision, cold-worked seamless steel pipe (SMLS Pipe)."
Tags:
Previous
Relevant Project
Address: Hengtai Road,Daqiuzhuang Town,Jinghai County,Tianjin,China
Mob: +8615122229899(whatspp)
Phone: +86 22 58171905
Fax: +86 22 58171902
E-mail:info@lefinsteel.com
Get company updates
Tianjin Lefin Industrial Co.,Ltd. All rights reserved City sub-station SEO www.300.cn