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| Type: | Seamless |
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| Technique: | Hot Rolled |
| Material: | Alloy Steel |
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Both steel pipes belong to the high-end alloy structural steel series. 30CrNi2MoV steel pipes excel in terms of ultimate strength and hardness.
Materials must simultaneously meet the following 5 core performance requirements:
| Material Category | Core Composition (Typical) | Key Performance Advantages | Application Scenarios |
| Chromium-molybdenum alloy structural steel | C 0.30-0.45%, Cr 1.0-1.5%, Mo 0.2-0.4% | High strength, good hardenability and thermal stability, strong resistance to tempering softening | Small and medium-caliber EQUIPMENT (e.g., mortars, anti-aircraft ), early howitzers |
| Chromium-nickel-molybdenum alloy structural steel | C 0.35-0.45%, Cr 0.8-1.2%, Ni 1.5-2.5%, Mo 0.3-0.5% | Balanced high strength and toughness, excellent low-temperature impact performance, good fatigue resistance | Medium and large-caliber howitzers, |
| Chromium-molybdenum-vanadium alloy structural steel | C 0.38-0.45%, Cr 1.0-1.5%, Mo 0.4-0.6%, V 0.1-0.2% | Vanadium (V) forms carbides with carbon, significantly improving high-temperature strength and creep resistance, with stronger erosion resistance | High-pressure large-caliber EQUIPMENT |
| Special alloys (high-end fields) | High-strength maraging steel, powder metallurgy high-speed steel | Higher ultimate strength (tensile strength > 2000MPa), far superior erosion and fatigue resistance compared to traditional steels | Large-caliber ultra-high pressure (e.g., 120mm/125mm smoothbore), experimental electromagnetiC |
Ultra-high strength and hardness: To withstand the instantaneous high pressure during using (preventing pipe expansion, deformation, or rupture), it usually requires yield strength ≥ 1200MPa, tensile strength ≥ 1400MPa, and surface hardness (after heat treatment) reaching HRC 35-45.
Good toughness and impact resistance: To prevent fatigue and brittle fracture during low-temperature or repeated firing (especially at the STEEL PIPE tail and the start of the rifling), it must ensure an impact energy ≥ 30J at -40°C.
Excellent heat resistance and erosion resistance: High-temperature gas will erode the inner wall of the pipe (forming "erosion," leading to rifling wear and caliber expansion). The material must maintain strength above 300°C and form a chromium oxide protective film through chromium elements to reduce erosion.
High fatigue resistance: Pipe needs to use repeatedly (usually with a service life requirement of 500-2000 rounds). The material must resist fatigue damage caused by the "high pressure-cooling" cycle to avoid pipe cracking.
Good machinability: The Pipe needs to be processed with rifling (spiral grooves to improve projectile stability). The material must have certain machinability and plasticity to avoid cracks during processing.
III. Examples of Typical Materials (Commonly Used at Home and Abroad)
China: 30CrNi2MoV steel
· A medium-carbon alloy structural steel containing 0.27-0.34% carbon, 0.6-0.9% chromium, 2.0-2.5% nickel, 0.3-0.5% molybdenum, and 0.1-0.2% vanadium. It is the mainstream material for domestic 155mm howitzers and 125mm, with a tensile strength of 1500-1800MPa and a service life of 800-1200 rounds.
· USA: 4340 steel (improved type)
· · A chromium-nickel-molybdenum steel (0.38-0.43% carbon, 0.7-0.9% chromium, 1.65-2.0% nickel, 0.2-0.3% molybdenum). It was originally used in howitzers, and the improved version (with added vanadium) is used in the 105mm, with excellent fatigue resistance.
· Germany: 34CrNiMo6 steel
· A commonly used steel pipe in Europe with a relatively high nickel content (1.3-1.7%). It has outstanding toughness and is suitable for operating in low-temperature environments. It also has good weldability (facilitating the connection between the pipe and the breech).
· Russia: 2A46 material (3V22 steel)
A chromium-molybdenum-vanadium steel with a slightly higher vanadium content (0.15-0.25%). It is specially designed for 125mm smoothbore , with strong erosion resistance and compatibility with armor-piercing , with a service life of approximately 600-800 rounds.
IV. Performance Enhancement Processes Beyond Material
The performance of the STEEL PIPE not only depends on the material but also needs to be optimized through subsequent processes. The core processes include:
Quenching and tempering: "Quenching + high-temperature tempering" transforms the steel structure into "tempered sorbite," balancing strength and toughness.
Inner wall chrome plating: Plating a 50-100μm layer of chromium on the inner wall of the STEEL PIPE improves erosion resistance and wear resistance, extending the service life by 30-50% (commonly used in SPECIAL EQUIPMENT).
Autofrettage: Applying high pressure to the inner wall of the Pipe through hydraulic or mechanical means to cause "plastic deformation" of the inner wall, forming "residual compressive stress" to offset part of the tensile stress during firing and improve fatigue resistance (a necessary process for large-caliber STEEL PIPE).
Precision forging of rifling: Using a precision forging machine to directly forge rifling (instead of cutting), reducing internal material defects and improving rifling strength and accuracy.
Q1: Why choose us?
A: Our company, as an internationally experienced and professional supplier, has been engaged in steel business for more than ten years. We can provide a variety of steel products with high quality to our clients.
Q2: Can you provide OEM/ODM service?
A: Yes. Please feel free to contact us for more details.
Q3:What is your terms of payment?
A: 100% T/T advance.
30% T/T and balance against copy of documents.
30% T/T advance, balance L/C at sight.
Q4: Can we visit your factory?
A: Warmly welcome. Once we have your schedule, we will arrange the professional sales team to follow up your case.
Q5: Can you provide sample?
A: Yes. Sample is free for regular sizes, but the buyer needs to pay freight cost.
Q6: How long is your delivery time?
A: Regular lead time is 15 to 30 days after receiving deposit.
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