ASTM A519 4140 Tubes | AISI 4140 / UNS G41400 Seamless & Welded Steel Tubing
When engineers and project managers need tubing that can survive high pressure, heavy loads, heat, and continuous stress, ASTM A519 4140 tubes are usually at the top of the list. This grade belongs to the chrome molybdenum alloy steel family and is known worldwide for its high strength, excellent toughness, and long service life.
In real industrial use, we’ve supplied A519 Gr 4140 seamless steel tubing, AISI 4140 tubes, and AISI 4140 UNS G41400 tubes for applications like boilers, heat exchangers, hydraulic systems, power plants, automotive components, and heavy machinery. The reason is simple: this material offers a reliable balance of strength, durability, and machinability that standard carbon steel just can’t match.
As an experienced A519 Grade 4140 mechanical tubing exporter and stockist, we focus on delivering correct specifications, consistent quality, and dependable supply—because in critical equipment, material quality is not optional.
What is ASTM A519 Grade 4140 Steel Tubing?
ASTM A519 is a standard for seamless and welded carbon and alloy steel mechanical tubing. Within this standard, Grade 4140 is a popular Cr-Mo (chromium-molybdenum) alloy steel.
So when buyers search for:
- ASTM A519 4140 tubes
- Chrome moly steel ASTM A519 4140 boiler tubing
- A519 Gr 4140 seamless tubing
- Alloy steel AISI 4140 seamless tube
They are usually looking for a material that provides:
- Higher strength than plain carbon steel
- Better resistance to wear and fatigue
- Good performance at elevated temperatures
- Excellent response to heat treatment
In simple terms, 4140 A519 tubing is designed for tough jobs where failure is not an option.
ASTM A519 4140, AISI 4140, UNS G41400, and 1.7225 – What’s the Difference?
You’ll often see these names used together:
- ASTM A519 Grade 4140 steel tubing (standard + grade)
- AISI 4140 tubes (material designation)
- AISI 4140 UNS G41400 tubes (international identification number)
- AISI 4140 1.7225 seamless tubes (DIN / EN equivalent)
They all describe the same basic chrome-moly alloy steel, just under different standards. In practice, whether you order A519 4140 chrome alloy steel HF SMLS tubing or AISI 4140 UNS G41400 tubes, the core material properties remain the same.
Seamless vs Welded A519 4140 Tubing
We supply both:
- A519 Gr 4140 seamless steel tubing
- ASTM A519 AISI 4140 welded tubes / CrMo AISI 4140 welded tubing
Seamless Tubes
Seamless tubes are produced without a welded joint, which gives them:
- Better pressure resistance
- More uniform strength
- Higher reliability in critical applications
They are widely used in:
- Boilers and heat exchangers
- Hydraulic and pneumatic systems
- High-pressure mechanical components
- Oil & gas and power plant equipment
Welded Tubes
Welded tubes are more cost-effective and suitable for:
- Structural and general mechanical use
- Applications where extreme pressure is not the main concern
Both types meet ASTM A519 requirements—the right choice depends on your working pressure, safety needs, and budget.
Specification Chart – ASTM A519 4140 Tubes
Below is a typical specification overview for ASTM A519 Grade 4140 steel tubing supplied in seamless and welded form:
| Parameter | Details |
| Standard | ASTM A519 |
| Grade | 4140 |
| Material | Alloy Steel / Chrome Moly Steel |
| Equivalent Grades | AISI 4140, UNS G41400, DIN/EN 1.7225 |
| Manufacturing Process | Seamless (SMLS), Welded |
| Forms Available | Round, Square, Rectangular, Special Shapes |
| Size Range | OD: As per standard & custom requirements |
| Wall Thickness | Light to Heavy Wall |
| Length | Random, Fixed Cut Length |
| Heat Treatment | Annealed, Normalized, Quenched & Tempered (Q&T) |
| Surface Finish | Black, Bright, Pickled, Machined |
| End Finish | Plain, Beveled, Threaded |
| Testing | Chemical, Mechanical, Dimensional, NDT (if required) |
This flexibility in size, form, and heat treatment is one reason 4140 A519 tubing is so widely used across industries.
Chemical Composition of AISI 4140 / ASTM A519 Grade 4140
The performance of chrome molybdenum AISI 4140 tubes comes from their carefully controlled alloy chemistry. A typical composition is shown below:
| Element | Percentage (%) |
| Carbon (C) | 0.38 – 0.43 |
| Manganese (Mn) | 0.75 – 1.00 |
| Silicon (Si) | 0.15 – 0.35 |
| Chromium (Cr) | 0.80 – 1.10 |
| Molybdenum (Mo) | 0.15 – 0.25 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.040 |
This chromium + molybdenum combination is what gives A519 4140 steel chromoly tubing its high strength, good hardenability, and improved wear resistance compared to ordinary carbon steel.
Mechanical Properties of ASTM A519 4140 Tubes
The mechanical properties of ASTM A519 Grade 4140 steel tubing depend on the heat treatment condition. Typical values are:
| Property | Typical Value |
| Tensile Strength | 655 – 850 MPa |
| Yield Strength | 415 – 655 MPa |
| Elongation | 12 – 20% |
| Hardness | 197 – 302 HB (depending on condition) |
| Impact Resistance | Good (varies with heat treatment) |
In real-world terms, this means AISI 4140 tubes can be tailored through heat treatment to match your exact strength and toughness requirements—whether you need better machinability or maximum strength.
Applications of ASTM A519 4140 / AISI 4140 Tubes
Because of its strength and reliability, AISI 4140 heat exchanger tubes and mechanical tubes are widely used in:
- Power plants – Boilers and pressure components
- Heat exchangers – High-strength tubing requirements
- Oil & gas – Tools, shafts, mechanical parts
- Automotive – Axles, gears, shafts, suspension parts
- Heavy engineering – Hydraulic cylinders, spindles, machine parts
- General mechanical – High-stress components
Simply put, if an application needs strength + toughness + durability, ASTM A519 Grade 4140 steel tubing is a proven choice.
Why Engineers Prefer Chrome Moly A519 4140 Tubing
From practical field experience, alloy steel AISI 4140 tubes are chosen because they offer:
- High strength for heavy loads and pressure
- Excellent toughness to resist cracking and impact
- Good fatigue resistance for moving and rotating parts
- Strong wear resistance for long service life
- Good machinability compared to many higher-alloy steels
That’s why 4140 A519 tubing is trusted in critical mechanical and pressure applications around the world.
Why Customers Choose Us As Their Carbon Steel AISI 4140 Tubing Supplier in Mumbai?
As a carbon steel AISI 4140 tubing supplier in Mumbai and an international exporter, we focus on:
- Reliable sourcing from approved mills
- Wide stock of seamless and welded tubes
- Fast and safe deliveries
- Technical support for grade and size selection
- Honest documentation and full traceability
Our long-term customers value us because we understand how these tubes are actually used in the field, not just how they look on paper.
Carbon Steel AISI 4140 Tubing Supplier in Mumbai
ASTM A519 4140 tubes, also known as AISI 4140 / UNS G41400 / 1.7225 seamless tubes, are a trusted solution for high-strength mechanical and pressure applications. With their chrome-moly alloy composition, they deliver the performance, safety, and reliability that modern industries demand.
Whether you need chrome moly steel ASTM A519 4140 boiler tubing, A519 Grade 4140 mechanical tubing, or alloy steel AISI 4140 tubes for critical equipment, choosing the right specification and a dependable supplier makes all the difference.
Global Reach
ASC LLP boasts a robust global presence, committed to delivering unparalleled service and quality to clients around the world. Our dedication to prompt delivery and exceptional customer care sets us apart in the industry. Major corporations across the USA, Europe, Asia, and other regions place their trust in our high-quality 1020 round bars. This widespread trust underscores our reputation for reliability and excellence. By consistently meeting and exceeding the expectations of our international clientele, we continue to solidify our position as a leader in the global steel market.
Countries We Export To
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