GB/T 8162 25MnCr6 High Strength Low Alloy Seamless Steel Pipe for Structural Purpose
Product Details
GB/T 8162 Seamless Steel Pipe
,25MnCr6 Precision Steel Tube
,High Strength Low Alloy Seamless Pipe
GB/T 8162 25MnCr6 High-Strength Low-Alloy Seamless Pipe for Structural Use
Material Introduction
The “GB/T 8162 25MnCr6” refers to a seamless steel tube designated under the Chinese national standard GB/T 8162 (for structural use) that is made from a low-alloy, high-strength steel with nominal chemical designation “25MnCr6.” The alloying with Mn (manganese) and Cr (chromium) (and possibly additional trace elements) is intended to provide enhanced strength, toughness, and overall mechanical performance compared to plain carbon steels.
Specifications
-
Standard: GB/T 8162-2018 (implements from 2019-02-01)
-
Shape / Form: Round seamless tube
-
Outer Diameter / Wall Thickness: As per GB/T 17395 tolerances on diameter and wall thickness, with special allowances for hot-rolled vs cold-drawn.
-
Delivery Status: Hot-rolled (expanding) or cold-drawn (rolled), with possible heat treatments (annealing, normalizing, tempering) depending on negotiated contract.
-
Dimensional Tolerances: Tolerances for outer diameter, wall thickness, out-of-roundness, and end squareness as per GB/T 8162 / GB/T 17395.
Chemical Composition
| Steel Grade | C (wt %) | Mn (wt %) | Cr (wt %) | Si (wt %) | P (max) | S (max) |
|---|---|---|---|---|---|---|
| 25MnCr6 (typical) | 0.20 – 0.29 | 1.20 – 1.60 | 0.30 – 0.60 | ≤ ~0.30 | ≤ ~0.03 | ≤ ~0.03 |
| 25MnCr6 (alternate) | 0.22 – 0.32 | ~1.6 – 2.0 | ~0.8 – 1.1 | ≤ 0.4 | ≤ 0.03 | ≤ 0.03 |
| Q345 (GB low-alloy structural) | ~0.20 – 0.22 | ~1.0 – 1.6 | — | ~0.50 | ≤ 0.035 | ≤ 0.035 |
| 20CrMo (alloy structural) | ~0.18 – 0.23 | ~0.50 – 0.80 | ~0.90 – 1.20 | ~0.17 – 0.37 | ≤ 0.025 | ≤ 0.025 |
| A572 Grade 50 (US HSLA) | ≤ 0.23 | ~1.35 | — | 0.15 – 0.40 | ≤ 0.030 | ≤ 0.030 |
Mechanical Properties
| Steel Grade / Condition | Yield Strength (Rp0.2) [MPa] | Ultimate Tensile Strength (Rm) [MPa] | Elongation (A%) / Toughness |
|---|---|---|---|
| 25MnCr6 (quenched & tempered, typical) | — | 600 – 950 | ~13 % (elongation) |
| 25MnCr6 (alternate literature) | ≥ 785 | ≥ 980 | ≥ 9 % |
| Q345 (typical GB low alloy structural) | ~235 | ~470 – 600 | ~20 – 25 % |
| 20CrMo (quenched & tempered) | ~300 – 500 (depending on thickness) | ~540 – 850 | 12 – 18 % |
| A572 Grade 50 (ASTM) | 345 | 448 | ~18 % (in 200 mm specimen) |
Major Features
-
High strength-to-weight: The alloying with Mn and Cr allows the pipe to offer higher strength than plain carbon structural tubes, enabling lighter designs.
-
Good toughness and ductility: With appropriate heat treatment, the material can maintain acceptable toughness and elongation for structural service.
-
Better hardenability and fatigue resistance: The alloying elements help delay crack initiation and propagation under cyclic loads.
-
Weldability and fabricability: Although alloyed, with controlled carbon equivalent and proper preheating/heat input, the steel can be welded and processed much like structural steels.
-
Consistency and reliability: As a seamless pipe, it avoids the weld seam issues of welded tubes and ensures uniform grain structure and performance in radial direction.
Applicable Standards
Here are relevant standards (international and regional) that are comparable or sometimes referenced in structural seamless tubes:
-
GB/T 8162-2018 — Seamless Steel Tubes for Structural Purposes
-
GB/T 17395 — Dimensions, shapes, weights and tolerances for seamless steel tubes
-
ASTM A572 / A992 — High-strength, low-alloy structural steels
-
EN 10210 (Parts 1, 2, 3) — Hot-finished structural hollow sections (non-alloy and fine-grain steels, also high-strength/weather-resistant versions)
-
ISO / EN / JIS / Russian GOST equivalents (not directly for 25MnCr6 but in the domain of structural seamless tubes)
-
If the user’s contract calls for impact testing, dimensional tolerances, or non-destructive testing (e.g., ultrasonic, eddy-current), those are also to be referenced from the standard’s test & inspection clauses in GB/T 8162.
Application Domains
| Broad Application Field | Specific Use Cases | Role / Benefits of 25MnCr6 Seamless Pipe |
|---|---|---|
| Construction & Civil Engineering | Steel structures (frames, braces, trusses, columns) | High strength allows thinner-walled members, durability, better safety margins |
| Mechanical / Machinery | Shafts, rollers, bolster tubes, support columns | Good fatigue & toughness properties, reliable geometry, long service life |
| Infrastructure / Utilities | Towers, masts, scaffolding pipes, support poles | Seamless integrity and high strength give robust performance under wind, dynamic loads |
| Transportation / Vehicles | Underframe members, chassis cross-members, structural tubes | Weight-saving and high strength help in vehicle structural components |
| Petrochemical / Offshore Structures (non-pressure) | Structural supports, pipe racks, frames | Corrosion and strength balance, must meet structural specification rather than internal pressure demands |
Q: Are you trading company or manufacturer ?
A: manufacturer,also can do trading.
Q: How long is your delivery time?
A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,
it is according to quantity.
Q: Do you provide samples? is it free or extra ?
A: Yes, we could offer the sample for free charge but need pay the cost of freight.
Q: What is your terms of payment ?
A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.
If you have another question, pls feel free to contact with me.
-
Auto Parts ASTM A513 Cold Rolling Welded Steel Tubes with DOM Production
Auto Parts ASTM A513 Welded Steel Tubes with DOM production ASTM A513 Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing Applications: for Machinery, Mechanical Engineering 1. Standard: ASTM A513 cold rolling welded precision steel tubes 2. Steel Grade: SAE1010, SAE1020, other materials upon agreement with customers. 3. Production method: Cold rolling on the weled steel tubes, to reach high accuracy on the OD and WT tolerance 4. Size range: O.D.:6-350mm W.T. -
25mm Diameter Bright Annealing Seamless Steel Tube for Hydraulic Systems
EN10305-1 E235 E355 NBK Bright Annealing Precision Steel Pipes for Hydraulic Systems EN10305-1 NBK Bright Annealed Precision steel pipes for Hydraulic system OD:4-80 (mm) WT0.5-10 (mm) Length 1000-12000mm Product name: Seamless Precision Steel Pipe Application: for hydraulic systems precision steel pipes for Hydraulic system OD (mm) WT (mm) Length (mm) 4 0.5 5800-6000 4.0 1.0 5800-6000 5.0 1.0 5800-6000 6.0 1.0 5800-6000 6.0 1.5 5800-6000 8.0 1.0 5800-6000 9.5 0.89 5800-6000 -
Precision Seamless Black Phosphating Steel Tube for Hydraulic Systems
Steel Pipes with high precision for Hydraulic Systems with Black Phosphating surface Black Phosphated Hydraulic Tubes with High Precision and tight tolerance, the tubes are produced by precision cold drawn and cold rolling, then bright annealed in a protected atmosphere, afterwards it is blackphosphated on the surface Production process: DIN series tubes, cold drawn and bright annealed precision seamless steel tube is used as the tube to be phosphated. The phosphorization is -
Precision Seamless Galvanized Steel Tubes DIN2391 EN103052 ST35.0 ST37
Precision Seamless Galvanized Steel Tubes DIN2391 EN103052 ST35.0 ST37 Production Process: Cold rolling by Cold pilger machine and Cold rolling machine,galvanized and zinc plated could be applied. Cold Rolled and Galvanized Steel Tube Production process: DIN highly accurate, cold rolled and bright seamless steel tube is used as the tube to be galvanized. The outer wall of tube is electroplated. The caps are covered at two ends of tube to prevent from the dust. Main Features:
