If you need strong, precise seamless tubing for hydraulic cylinders, 自動車部品, or structural frames, drawn over mandrel (DOM) 鋼鉄 ゴールドスタンダードです. Unlike welded or standard seamless tubing, DOM steel has a uniform wall thickness and smooth inner surface—making it ideal for high-pressure and precision applications. このガイドは、あなたが選択するために知っておくべきすべてを分解します, 使用, and source DOM steel effectively.
1. Drawn Over Mandrel (DOM) 鋼鉄: Manufacturing Techniques
DOM steel’s superior quality starts with a rigorous, multi-step manufacturing process. Here’s how it’s made, from raw material to finished tubing:
- Start with Seamless Steel Tubing: The process begins with seamless steel tubing (made via extrusion or piercing). This ensures no weld seams, which can weaken tubing under pressure.
- アニーリング: The seamless tubing is heated to 800–900°C and cooled slowly (アニーリング). This softens the steel, making it easier to shape during drawing.
- Mandrel Insertion: A solid metal rod called a mandrel is inserted into the seamless tubing. The mandrel keeps the tube’s inner hole open and ensures uniform inner diameter (ID) during drawing.
- Cold Drawing: The tubing (with mandrel inside) is pulled through a series of 死ぬ (shaped openings) in a drawing machine. This reduces the outer diameter (OD) and wall thickness while stretching the tube to length. コールドワーク during this step strengthens the steel.
- トリミング & 切断: After drawing, the tubing is cut to standard lengths (例えば。, 6ft, 12ft) or custom sizes using precision saws.
- Final Heat Treatment: Optional but common—another round of annealing to reduce stress from cold drawing, or tempering to boost hardness for wear-prone parts.
- 検査: The finished DOM tubing undergoes dimensional checks (OD, ID, wall thickness) and surface inspections to ensure quality.
本当の例: A hydraulic cylinder manufacturer in Germany uses DOM steel tubing. Theprecision manufacturing process ensures the tubing can handle 3,000 psi of hydraulic pressure without leaking—critical for heavy machinery.
2. Drawn Over Mandrel (DOM) 鋼鉄: 材料特性
DOM steel’s unique manufacturing process gives it standout properties that make it better than welded or standard seamless tubing. パフォーマンスは次のとおりです:
| 財産 | 典型的な値 (Mild Steel DOM) | Advantage Over Welded Tubing |
|---|---|---|
| 抗張力 | 450–600 MPa | 20–30% higher (no weak weld seams) |
| 降伏強度 | 300–400 MPa | Resists bending or deformation under load |
| 伸長 | 15–25% | Ductile enough to form into shapes (例えば。, 曲がり) |
| 壁の厚さ | ±0.05mm許容範囲 | Uniform—avoids thin spots that can burst |
| Inner Surface Finish | RA0.8-1.6μm | Smooth—reduces friction in hydraulic systems |
| Roundness | ±0.1mm | Consistent shape—fits bearings and connectors |
| Fatigue Resistance | 10^6+ load cycles | Lasts longer in repetitive-use parts (例えば。, シャフト) |
キープロパティ: 寸法精度
DOM steel’sdimensional accuracy is its biggest strength. 例えば, a 10mm OD DOM tube has an OD tolerance of just ±0.05mm—this means it will fit perfectly with connectors or bearings, no extra machining needed. Welded tubing, 対照的に, often has ±0.2mm tolerance, requiring additional work.
Material Composition
Most DOM steel is mild carbon steel (アイシ 1018 is common) と:
- 炭素 (c): 0.15–0.20% (balances strength and ductility)
- マンガン (Mn): 0.60–0.90% (boosts tensile strength)
- 鉄 (fe): 98–99％ (base metal)
For corrosion-resistant needs, stainless steel DOM tubing (SUS304/SUS316) 利用可能です, with chromium (18–20％) and nickel (8–10％) added to prevent rust.
3. Drawn Over Mandrel (DOM) 鋼鉄: Applications and Uses
DOM steel’s strength, 精度, and seamless design make it essential in industries where reliability matters. これがそのトップの使用です:
産業機械
- 油圧シリンダー: DOM tubing’s smooth inner surface reduces friction between the piston and tube, preventing leaks. A construction equipment maker uses DOM steel for excavator hydraulic cylinders—they last 50% longer than those made with welded tubing.
- Pneumatic cylinders: Similar to hydraulic cylinders, DOM steel handles compressed air pressure without bursting.
自動車産業
- Suspension components: DOM steel bars make up sway bars and control arms—their high tensile strength resists bending during sharp turns.
- ドライブシャフト: DOM tubing’s uniform wall thickness ensures balanced rotation, reducing vibration in cars and trucks.
工事 & Structural
- Furniture frames: DOM steel tubes are used for heavy-duty office chairs and gym equipment—they’re strong but lightweight. A fitness brand uses DOM steel for treadmill frames; the tubes support 300kg of weight without bending.
- Tubular structures: DOM steel forms railings and support posts in buildings—its straightness (±0.5mm per meter) ensures a clean, プロの表情.
専門的な用途
- Marine applications: Stainless steel DOM tubing resists saltwater corrosion, making it ideal for boat rigging and hydraulic systems.
- 医療機器: DOM steel is used for surgical tool handles—its smooth surface is easy to sterilize and doesn’t harbor bacteria.
4. Drawn Over Mandrel (DOM) 鋼鉄: Quality and Standards
To ensure you’re getting high-quality DOM steel, look for compliance with global standards and strict quality control measures.
重要な基準
| 標準組織 | Common Specs | 使用事例 |
|---|---|---|
| ASTM (私たち。) | ASTM A513 (DOM steel tubing) | 油圧シリンダー, 自動車部品 |
| アイシ (私たち。) | アイシ 1018 (mild steel DOM), アイシ 304 (stainless DOM) | Structural frames, 医療ツール |
| JIS (Japan) | JIS G3445 (DOM seamless tubing) | Marine equipment, 産業機械 |
| DIN (ヨーロッパ) | DIN EN 10305-1 (precision DOM tubing) | Pneumatic cylinders, precision shafts |
| ISO (グローバル) | ISO 8539 (DOM steel for hydraulic use) | High-pressure hydraulic systems |
品質管理対策
Reputable manufacturers use these steps to ensure DOM steel quality:
- Chemical Analysis: Tests check for carbon, マンガン, and other alloying elements to confirm they meet specs (例えば。, 0.18% carbon for AISI 1018).
- 寸法検査: Calipers and laser scanners verify OD, ID, wall thickness, and straightness—ensuring they stay within tolerance.
- Non-Destructive Testing (NDT): Ultrasonic testing checks for internal defects (例えば。, ひび割れ) that can’t be seen with the naked eye.
- 表面検査: Visual checks or profilometers ensure the outer and inner surfaces are smooth (no scratches or pits).
- Mechanical Testing: Tensile tests measure strength, while bend tests check ductility—samples are pulled or bent until they break to confirm performance.
ヒントの場合: Always ask for a Certificate of Compliance (COC) or Mill Test Report (MTR) when buying DOM steel. These documents prove the tubing meets your chosen standard.
Yigu Technologyの視点
Yiguテクノロジーで, お勧めしますdrawn over mandrel (DOM) 鋼鉄 for clients needing high-pressure, precision tubing. We supply ASTM A513 DOM steel (mild steel and stainless steel) with tight tolerances (±0.03mm for wall thickness) for hydraulic and automotive projects. Our quality checks include ultrasonic NDT and dimensional scans, so clients trust the tubing can handle tough conditions. We also offer custom cutting to reduce waste—for example, a hydraulic client saved 15% on material costs by ordering 8ft custom lengths instead of standard 12ft tubes.
よくある質問
- Is DOM steel better than seamless steel for hydraulic cylinders?
Yes—standard seamless steel has less uniform wall thickness (±0.1mm許容範囲) and a rougher inner surface. DOM steel’s ±0.05mm tolerance and smooth ID reduce friction and leaks, making it more reliable for hydraulic systems. - Can DOM steel be bent or welded?
Yes—DOM steel is ductile enough for bending (use a tube bender to avoid kinks). It also welds well with MIG or TIG welding, but preheat to 150–200°C first to reduce stress from cold working. - How do I choose between mild steel and stainless steel DOM tubing?
Choose mild steel DOM for indoor, dry applications (例えば。, 家具, 自動車部品)—it’s cheaper. Choose stainless steel DOM for outdoor, 濡れた, or corrosive environments (例えば。, 海兵隊, 医学)—it resists rust but costs more.
