قضيب تيتانيوم من الدرجة الثانية وفقًا لمعيار ASTM B348
- معيار: ASTM B348
- درجة: Grade 2 (Commercially Pure Titanium)
- الأمم المتحدة: R50400
- حالة: مُلدّن
- القطر: φ7 ~ φ300 مم
- Typical Industrial Bar Length: 200–3000 mm
تتوفر أحجام قابلة للتخصيص، بينما يجب تأكيد معايير المنتج المحددة وفقًا للإصدار القياسي والطلب المعمول بهما.
نظرة عامة على المنتج
ASTM B348 Grade 2 titanium bar is an unalloyed, commercially pure titanium bar produced and tested to ASTM B348/B348M. Its UNS designation is R50400. Material performance is developed by controlling oxygen, iron, nitrogen, carbon and hydrogen, together with hot working, annealing and grain condition.
Grade 2 is one of the most widely used commercially pure titanium grades. It is stronger than Grade 1 while retaining better ductility and forming capability than Grades 3 and 4. This balance of strength, elongation, weldability and corrosion resistance makes Grade 2 the general-purpose workhorse of commercially pure titanium.
Grade 2 bar is used for corrosion-resistant fasteners, shafts, valve stems, flanges, connectors, electrode components and heat-exchanger parts in chemical processing, desalination, marine, chlor-alkali, electroplating, energy and general industrial equipment.
| مواصفة | تفاصيل |
| المعيار الصناعي | ASTM B348 |
| Industrial Grades | Gr2 |
| نطاق القطر | Ø7 – Ø300 mm |
| الأقطار النموذجية | Ø7, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 150, 200 mm |
| Typical Industrial Bar Length | 200–3000 mm; cut-to-length available |
| Surface / Supply Condition | Hot-rolled black surface / Turned / Ground |
| Precision Tolerance | h6 / h7 / h8 available subject to diameter, finishing process and order confirmation |
الخصائص الرئيسية
- Balanced strength and ductility: The room-temperature minimum tensile strength is 345 MPa and minimum specified elongation is 20%, supporting moderate-strength applications with useful plasticity.
- Excellent corrosion resistance: A continuous, adherent titanium-oxide passive film forms naturally and can repassivate when oxygen or moisture is present.
- High strength-to-weight potential: Density is approximately 4.51 g/cm³, substantially below that of ordinary steel.
- Good hot and cold workability: Grade 2 may be forged, rolled, extruded, drawn, bent, stamped, spun and machined.
- قابلية جيدة للحام: TIG, MIG, plasma, laser and electron-beam processes may be used with complete inert-gas protection of all hot metal.
- Good low-temperature behavior: CP titanium retains useful ductility and toughness at low temperatures.
- Essentially non-magnetic: This can be useful in equipment sensitive to magnetic response.
- لم يتم تعزيزها بشكل ملحوظ بالمعالجة الحرارية التقليدية: Annealing is used mainly for stress relief, ductility recovery and microstructural stabilization.
التركيب الكيميائي
ASTM B348 Grade 2 chemistry is controlled to the following mass-percent limits:
| عنصر | ASTM B348 Grade 2 requirement |
| النيتروجين، N | ≤0.030% |
| الكربون، C | ≤0.080% |
| الهيدروجين، H | ≤0.015% |
| الأكسجين، O | ≤0.250% |
| الحديد، Fe | ≤0.300% |
| العناصر المتبقية، كل منها | ≤0.100% |
| العناصر المتبقية، الإجمالي | ≤0.400% |
| التيتانيوم، Ti | توازن |
Technical references: ASTM B348/B348M and TIMETAL 50A, a material corresponding to ASTM Grade 2.
- الأكسجين والحديد: Important strength-controlling elements in CP titanium; higher levels generally increase strength and hardness but may reduce ductility and formability.
- Hydrogen: Must be controlled because excessive pickup can form brittle hydrides and increase embrittlement risk.
- محتوى التيتانيوم: ASTM states Titanium: Balance. Grade 2 should not be simplified to a fixed claim such as “Ti ≥99.5%.”
- Lot acceptance: Final chemistry shall be confirmed by the original mill test report for the applicable heat.
Mechanical Requirements
The following room-temperature tensile requirements apply to annealed ASTM B348 Grade 2 bar. The specified edition, dimensions, specimen form and test orientation must also be considered for formal acceptance.
| ملكية | متطلبات | حالة |
| قوة الشد القصوى، Rm | ≥345 MPa | الحد الأدنى من معايير ASTM |
| قوة خضوع الإزاحة 0.2%، Rp0.2 | ≥275 MPa | الحد الأدنى من معايير ASTM |
| استطالة في طول القياس المحدد | ≥20% | الحد الأدنى من معايير ASTM |
| تقليص المساحة | ≥30% | الحد الأدنى من معايير ASTM |
Typical Room-Temperature Properties (Not Guaranteed)
| ملكية | Reference Value |
| أقصى قوة شد | Approx. 485 MPa |
| قوة خضوع الإزاحة 0.2% | Approx. 345 MPa |
| استطالة | Approx. 28% |
| تقليص المساحة | Approx. 57% |
| معامل المرونة | حوالي 105-120 جيجا باسكال |
| Typical bend radius | Approx. 2.5T, dependent on condition and thickness |
مهم: Typical data are not ASTM acceptance values and are not automatically guaranteed for every lot. Hardness is not a universal core acceptance criterion for ASTM B348 Grade 2. If hardness, fatigue or bend performance is required, it should be stated separately in the purchase order.
خدمات التوريد والجودة من HTN
ASTM B348 Grade 2 titanium bar is produced by evaluated, qualified mill resources. HTN confirms technical requirements from customer drawings and purchase specifications, selects a mill with the appropriate capability, reviews the original MTR and heat/lot records, and verifies the relationship among the material standard, dimensions, quantity, condition and inspection documents.
When agreed in the contract, HTN can coordinate independent retesting, ultrasonic examination, PMI, cut-to-length service, turning or grinding, EN 10204 3.1 documentation and third-party inspection, together with export packing, shipping documents and international delivery.
التطبيقات النموذجية
- Shafts, valve stems, flanges, fasteners and connectors for chemical equipment;
- Components for heat exchangers, condensers, evaporators and reactors;
- Desalination, shipboard and marine-engineering equipment;
- Pump shafts, supports and corrosion-resistant machined parts;
- Chlor-alkali, electroplating and electrochemical equipment;
- Petrochemical, energy and general industrial equipment;
- Non-high-strength aircraft brackets, duct accessories and secondary structures;
- Engineering parts requiring a balance of light weight, corrosion resistance and moderate strength.
املأ النموذج أدناه وسيسعد فريقنا بمساعدتك
خصائص التصنيع والمعالجة
Machining
Grade 2 can be turned, milled, drilled, ground and threaded. Because titanium has low thermal conductivity, noticeable elastic recovery and a tendency to gall, sharp rigid tools, low cutting speed, stable feed and abundant non-chlorinated cutting fluid are recommended. Dwell and rubbing should be avoided.
التشكيل على البارد
Grade 2 has good room-temperature bending, stamping, drawing and spinning capability. Work hardening and substantial springback must be considered. Intermediate annealing or hot sizing may be used for complex forming.
Hot working
Hot forging, rolling, extrusion and pressing may be used. Temperature, soak time, reduction and atmosphere should follow a qualified procedure to limit abnormal grain growth, surface oxidation and alpha-case formation.
اللحام
Grade 2 has good weldability. The weld pool, face, root and hot heat-affected zone must be fully protected by high-purity inert gas to prevent oxygen, nitrogen and hydrogen contamination.
Wear resistance
Unalloyed titanium tends to gall and smear and is not recommended for high-friction sliding pairs without an appropriate coating, surface treatment, bushing or mating-material design.
السلامة أثناء التشغيل الآلي: Fine titanium chips and powders are combustible. They must be collected, stored and handled away from ignition sources in accordance with applicable fire and occupational-safety requirements.
الخصائص الفيزيائية النموذجية
The following are typical reference values near room temperature and are not mandatory lot-acceptance requirements of ASTM B348:
| الخصائص المادية | Typical value |
| كثافة | حوالي 4.51 جم/سم³ |
| معامل المرونة | حوالي 105-120 جيجا باسكال |
| الحرارة النوعية عند درجة حرارة الغرفة | حوالي 0.52 جول/(غرام·كلفن) |
| الموصلية الحرارية | Approx. 21.8 W/(m·K) |
| المقاومة الكهربائية | Approx. 0.53 μΩ·m |
| متوسط معامل التمدد الحراري، 20-100 درجة مئوية | حوالي 8.6 × 10⁻⁶/كلفن |
| Mean CTE, 20–300°C | Approx. 9.5×10⁻⁶/K |
| بيتا ترانس | Approx. 915°C |
| نطاق الانصهار | Approx. 1650–1670°C |
| نسبة بواسون | حوالي 0.34 |
| المغناطيسية | يُعتبر عموماً غير مغناطيسي |
Physical-property references: TIMETAL 50A and Carpenter Technology CP Titanium Grade 2 data. Values vary with temperature, heat, orientation and processing condition.
مقاومة التآكل
The corrosion resistance of Grade 2 titanium bar is based on a continuous, tightly adherent passive titanium-oxide film. If the film is slightly damaged, it generally reforms when oxygen or moisture is available.
Environments in Which Grade 2 Generally Performs Well
- Natural seawater, marine atmospheres, salt spray and flowing seawater;
- neutral chlorides, brines and many chloride-bearing aqueous solutions;
- nitric acid and many oxidizing acid environments;
- wet chlorine and hydrated halogen environments where sufficient moisture is present;
- many alkaline solutions, organic compounds and aqueous salt solutions;
- desalination, heat-exchange, chlor-alkali and electroplating service.
بيئات تتطلب تقييمًا دقيقًا
- Hot, concentrated or oxygen-starved strongly reducing acids;
- tight crevices and deposits in hot concentrated chloride or sulfate solutions;
- fluoride-bearing media or hydrofluoric acid;
- anhydrous methanol or halide-contaminated methanol;
- red fuming nitric acid and molten chloride salts;
- liquid mercury, cadmium and related special environments;
- completely dry chlorine service;
- pickling, cathodic protection or electrochemical conditions that may promote hydrogen pickup.
تحذير هندسي: Corrosion behavior depends on concentration, temperature, pH, aeration, velocity, impurities, crevices, deposits, residual stress, surface condition and dissimilar-metal contact. Product literature supports preliminary material selection but cannot replace corrosion testing and engineering review under the actual service conditions.
Typical Industry Manufacturing Route for Grade 2 Titanium Bar
- تحضير المواد الخام: Select qualified titanium sponge and approved clean revert, controlling oxygen, iron, nitrogen, carbon, hydrogen and foreign contamination.
- تحضير القطب الكهربائي: Compact the charge into electrode blocks and assemble a melting electrode while excluding oil, moisture and iron-bearing foreign matter.
- الصهر الفراغي وإنتاج السبائك: Use VAR, electron-beam cold-hearth melting or another approved titanium melting route. The route and number of melts follow the qualified mill process and purchase requirements.
- معالجة السبائك وتركيبها الكيميائي: Crop, peel or grind the ingot as necessary, complete the required chemical analysis and retain clear heat identification.
- Breakdown forging: Upset, draw or multi-directionally forge the ingot to break down the cast structure, improve internal uniformity and produce billet for further working.
- Bar formation: Forge, hot roll, extrude, draw or combine processes to produce the required section. Precision small bars may be turned or centerless ground.
- Heat treatment: Anneal to reduce residual stress, improve uniformity and obtain the required strength-ductility balance. The actual temperature and hold time follow the qualified procedure.
- Surface conditioning: Turn, grind, blast, pickle or combine processes to remove scale and alpha case. Pickling must be controlled to limit hydrogen pickup.
- التمليس والتشطيب: Straighten, cut, chamfer, turn, grind or polish to achieve the specified diameter, length, straightness and surface quality.
- Final inspection: Verify chemistry, room-temperature tensile properties, dimensions, tolerances, straightness, surface condition and product identification.
- Documentation and traceability: Maintain the relationship among the physical material, labels, heat number, lot, dimensions and original mill test report.
- Packing and delivery: Protect the finished surface and use suitable export packing and transport markings to prevent impact, scratching, moisture and dissimilar-metal contamination.
Melting and inspection note: ASTM B348 does not prescribe a fixed double- or triple-VAR route for every Grade 2 bar. UT, PT, PMI, microstructure, hardness, EN 10204 3.1 and third-party inspection must be ordered when required.
