Drawn Over Mandrel (DOM) فُولاَذ: The Guide to Manufacturing, ملكيات & يستخدم

If you need strong, precise seamless tubing for hydraulic cylinders, قطع غيار السيارات, or structural frames, drawn over mandrel (DOM) فُولاَذ هو المعيار الذهبي. 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. هذا الدليل يكسر كل ما تحتاج إلى معرفته للاختيار, يستخدم, and source DOM steel effectively.

1. Drawn Over Mandrel (DOM) فُولاَذ: 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:

1. 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.
2. الصلب: The seamless tubing is heated to 800–900°C and cooled slowly (الصلب). This softens the steel, making it easier to shape during drawing.
3. 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.
4. Cold Drawing: The tubing (with mandrel inside) is pulled through a series of يموت (shaped openings) in a drawing machine. This reduces the outer diameter (OD) and wall thickness while stretching the tube to length. العمل البارد during this step strengthens the steel.
5. تقليم & قطع: After drawing, the tubing is cut to standard lengths (على سبيل المثال, 6ft, 12ft) or custom sizes using precision saws.
6. 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.
7. تقتيش: The finished DOM tubing undergoes dimensional checks (OD, ID, wall thickness) and surface inspections to ensure quality.

مثال حقيقي: A hydraulic cylinder manufacturer in Germany uses DOM steel tubing. الprecision manufacturing process ensures the tubing can handle 3,000 psi of hydraulic pressure without leaking—critical for heavy machinery.

2. Drawn Over Mandrel (DOM) فُولاَذ: خصائص المواد

DOM steel’s unique manufacturing process gives it standout properties that make it better than welded or standard seamless tubing. إليك كيفية أداءها:

خاصية رئيسية: دقة الأبعاد

DOM steel’sdimensional accuracy is its biggest strength. على سبيل المثال, 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, على النقيض من ذلك, often has ±0.2mm tolerance, requiring additional work.

Material Composition

Most DOM steel is mild carbon steel (AISI 1018 is common) مع:

• الكربون (ج): 0.15–0.20% (balances strength and ductility)
• المنغنيز (MN): 0.60–0.90% (boosts tensile strength)
• حديد (Fe): 98-99 ٪ (base metal)
  For corrosion-resistant needs, stainless steel DOM tubing (SUS304/SUS316) متاح, with chromium (18-20 ٪) and nickel (8-10 ٪) added to prevent rust.

3. Drawn Over Mandrel (DOM) فُولاَذ: Applications and Uses

DOM steel’s strength, دقة, and seamless design make it essential in industries where reliability matters. فيما يلي أهم استخداماتها:

الآلات الصناعية

• الأسطوانات الهيدروليكية: 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.

صناعة السيارات

• Suspension components: DOM steel bars make up sway bars and control arms—their high tensile strength resists bending during sharp turns.
• مهاوي القيادة: DOM tubing’s uniform wall thickness ensures balanced rotation, reducing vibration in cars and trucks.

بناء & 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, نظرة احترافية.

الاستخدامات المتخصصة

• Marine applications: Stainless steel DOM tubing resists saltwater corrosion, making it ideal for boat rigging and hydraulic systems.
• المعدات الطبية: 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) فُولاَذ: Quality and Standards

To ensure you’re getting high-quality DOM steel, look for compliance with global standards and strict quality control measures.

المعايير الرئيسية

تدابير مراقبة الجودة

Reputable manufacturers use these steps to ensure DOM steel quality:

1. Chemical Analysis: Tests check for carbon, المنغنيز, and other alloying elements to confirm they meet specs (على سبيل المثال, 0.18% carbon for AISI 1018).
2. التفتيش الأبعاد: Calipers and laser scanners verify OD, ID, wall thickness, and straightness—ensuring they stay within tolerance.
3. اختبار غير التدمير (NDT): Ultrasonic testing checks for internal defects (على سبيل المثال, تشققات) that can’t be seen with the naked eye.
4. فحص السطح: Visual checks or profilometers ensure the outer and inner surfaces are smooth (no scratches or pits).
5. Mechanical Testing: Tensile tests measure strength, while bend tests check ductility—samples are pulled or bent until they break to confirm performance.

للنصيحة: 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.

منظور Yigu Technology

في Yigu Technology, نوصيdrawn over mandrel (DOM) فُولاَذ 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.

التعليمات

1. Is DOM steel better than seamless steel for hydraulic cylinders?
   Yes—standard seamless steel has less uniform wall thickness (± 0.1mm التسامح) 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.
2. 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.
3. How do I choose between mild steel and stainless steel DOM tubing?
   Choose mild steel DOM for indoor, dry applications (على سبيل المثال, أثاث, قطع غيار السيارات)—it’s cheaper. Choose stainless steel DOM for outdoor, مبتل, or corrosive environments (على سبيل المثال, البحرية, طبي)—it resists rust but costs more.