Discharge port of oxidation reactor of PTA plant, Drawing to write TA10 butt welding flange, Supplier supplied as TA2 plate flange, Seemingly similar materials, actually"Two Structures": Plate flange at PN1.6 MPa + 120℃ conditions, 1-2 years weld cracking leakage;TA10 butt welding flange has been running for 8 years under the same working condition without abnormality.This article systematically explainsTitanium flange 4 types of structure, 7 types of medium matching, domestic vs import price, 5 steps to avoid pits, it is recommended to collect.
Core conclusions:Titanium flangeIt's not as simple as "titanium + flange"_Wrong structure equals no choice。Plate/butt welding/thread/loose sleeve 4 types of structures have applicable working conditions, Wrong choice 1-2 year seal failure, Choose 15+ years without fault.
Although the flange is small, it performs three key functions:
An anti-common sense:In chemical media,80% of flange failures are not flange body corrosion, but seal surface leakage。Insufficient sealing surface hardness, excessive roughness, gasket deformation-all lead to leakage.
Stainless steel flange pitting corrosion, crevice corrosion in the medium containing Cl, in reducing acid corrosion.Titanium Flangeself-repairing passivation filmmaking it in oxygen-containing Cl medium, dilute acid, There's no metal ion contamination in seawater--this is chloralkali., The desalination industry is switchingTitanium flangeThe reason.
| type | structural features | applicable pressure | typical application |
|---|---|---|---|
| ① Plate flange (PL) | Titanium Plate + bolted connection | PN≤1.6 MPa | Atmospheric pressure ~1.6 MPa equipment |
| ② Butt welding flange (WN) | Neck butt welding, high strength | PN≤4.0 MPa | High temperature and high pressure + frequent disassembly |
| ③ Threaded flange (Th) | pipe end threaded connection | PN≤1.6 MPa | Small caliber, low pressure, frequent maintenance |
| ④ Loose Flange (LJ) | Titanium ring + steel flange loop | PN≤1.6 MPa | Large caliber + cost reduction + corrosion prevention |
Figure 1: Category 4Titanium flange结构示意 ① 板式法兰 PL ② 对焊法兰 WN ┌────╮ ┌────╮ ┌──┐ │ ◯ │ ← 螺栓孔 │ ◯ │ │ │ ← 颈 │░░░░░│ ← 密封面 │░░░░░│ │ │ │░░░░░│ │░░░░░│ │ │ ╰────╯ ╰────╯ │ │ ← 焊口 ◀─ DN ─▶ ◀─ DN ─▶└──┘ ③ 螺纹法兰 Th ④ 松套法兰 LJ ┌────╮ ┌────╮ ← 钢法兰 │ ◯ │ ← 螺栓孔 │ ◯ │ │░░░░░│ ← 密封面 │░░░░░│ │░░░░░│ │░░░░░│ ← 钛环 │ ╲╱ │ ← 螺纹连接 │ ║║║║ │ ← 钢法兰 ╰────╯ ╰────╯ ◀─ DN ─▶ ◀─ DN ─▶ 【图 1】4 类Titanium Flangeschematic structural
Core selection logic:
| comparison item | Plate flange PL | Butt welding flange WN | Loose flange LJ |
|---|---|---|---|
| structural strength | centre | excellent | centre |
| applicable pressure | ≤1.6 MPa | ≤4.0 MPa+ | ≤1.6 MPa |
| processing difficulty | low | High (requires forging) | Medium (titanium ring + steel flange) |
| price | standard | +30-50% | Baseline-20% |
| Large caliber application | centre | excellent | Excellent (DN≥600 recommended) |
| risk of leakage | Medium (weld heat effect) | low | centre |
| media type | Preferred brand | proposed structure | specification interval |
|---|---|---|---|
| ① Seawater + neutral brine containing Cl | TA2 | Plate/butt weld | DN15-DN800 |
| ② Wet chlorine (80-120℃) | TA10 | butt welding(including gaps) | DN50-DN500 |
| ③ Dilute reducing acid (10% H ˇ SO) | TA9 / TA10 | butt welding | DN50-DN400 |
| ④ Dilute nitric acid/oxidizing acid | TA2 | plate-type | DN15-DN600 |
| PTA unit (containing Br acetic acid 120℃) | TA9 | butt welding | DN80-DN500 |
| Hydrometallurgy (Ni Co solution containing Cl) | TA2 / TA10 | Butt welding/loose sleeve | DN100-DN800 |
| ⑦ Pharmaceutical/food grade | TA2 High Purity | Butt welding (GMP grade) | DN15-DN300 |
Case 1: Titanium butt welding flange of wet chlorine preheater in a 600,000 ton/year caustic soda plant
Case 2: PTA oxidation reactor TA9 butt welding flange group
Case 3: Titanium loose sleeve flange group of a 6000-meter deep sea detector
Titanium flangeThe biggest difference between manufacturing and stainless steel flanges is that:
钛法兰来料检验（材质证明书 + Al/V 含量复验）
↓
锻造（β 锻造 850-950℃ 或自由锻）
↓
退火（700-790℃ × 1-2h 消除应力）
↓
粗加工（数控车，留 2-3 mm 余量）
↓
精加工（数控车到图纸尺寸）
↓
密封面加工（车削 + 研磨，Ra≤0.8μm）
↓
密封槽加工（数控铣）
↓
螺栓孔加工（数控钻 + 攻丝）
↓
100% PT 渗透检测
↓
酸洗钝化（HF:HNO₃ = 1:3，30-60 min）
↓
最终检验（尺寸 + 密封面 + 硬度 ≥180HV）
↓
包装（真空/充氮 + 木箱内衬 PE 膜）
| process | key parameter | Titanium special requirements | Consequences of failure |
|---|---|---|---|
| forge | Temperature 850-950℃ | Do not heat to oxidation color | coarse grain |
| sealing surface hardness | ≥ 180HV | Annealed ≥180HV (critical) | gasket deformation |
| sealing surface roughness | Ra ≤ 0.8μm | abrasive paste progressive polishing | seal leakage |
| flatness | ≤ 0.05%DN | Avoid titanium wire drawing | not tightly sealed |
| acid passivation | HF:HNO₃ = 1:3 | passivation film core | Loss of self-repair |
| standard number | standard name | applicable content |
|---|---|---|
| HG/T 20592-2009 | Steel pipe flanges (PN series) | Standard of Ministry of Chemical Industry of China (PN series) |
| GB/T 9112-2010 | Steel pipe flange type and parameters | GB flange type |
| GB/T 9124-2010 | Specification for steel pipe flanges | GB Technical Requirements |
| ASME B16.5-2020 | Pipe Flanges and Flanged Fittings | American Standard (Class Series) |
| ASME B16.47-2020 | Large Diameter Steel Flanges | American Standard Large Caliber |
| ASME B16.34-2020 | Valves Flanged Threaded and Welding End | valve flange |
| EN 1092-1:2018 | Circular Flanges for Pipes | European standard |
| JIS B2220-2012 | Steel Pipe Flanges | Japanese Industrial Standards |
| GB/T 12459-2017 | Steel butt welded seamless pipe fittings | geometric references |
| NB/T 47013.5-2015 | Non-destructive testing of pressure equipment-Part 5: Penetrant testing | PT test |
Key Reminder:GB/T 9112 + HG/T 20592 + ASME B16.5 are three mainstream systems.Export orders plus ASME double proofreading;ASME BPVC Section III.
| Specifications/Material/Structure | Domestic quotation (yuan/piece) | Import quotation (yuan/piece) | difference |
|---|---|---|---|
| TA2 plate DN50 PN1.6 | 120-180 | 280-380 | Import expensive 2 x |
| TA2 Plate DN100 PN1.6 | 180-260 | 400-520 | Import expensive 2 x |
| TA2 butt welding DN100 PN2.5 | 280-380 | 580-750 | Import expensive 2 x |
| TA10 butt weld DN200 PN1.6 | 800-1200 | 1800-2400 | Import expensive 2 x |
| TA9 butt weld DN300 PN1.0 | 1200-1800 | 2800-3600 | Import expensive 2 x |
| TA2 loose sleeve DN500 PN2.5 | 2500-3500 | 5800-7500 | Import expensive 2 x |
Purchasing Tips:
图 2：4 类密封面形式（FF/RF/MFM/TG）
① FF 平面密封（Flat Face） ② RF 突面密封（Raised Face）
┌─────────────┐ ┌─────────────┐
│░░░░░░░░░░░░░│ ← 平面 │ │
│░░░░░░░░░░░░░│ │░░░░░░░░░░░░░│ ← 凸面
│░░░░░░░░░░░░░│ ← 平面 │░░░░░░░░░░░░░│
└─────────────┘ └─────────────┘
适用：PN≤1.6 MPa 适用：PN≥2.5 MPa（最常用）
③ MFM 凹凸面密封 ④ TG 榫槽密封（Tongue & Groove）
┌─────────────┐ ┌─────────────┐
│ ┌───────┐ │ │░░░░░░░░░░░░░│ ← 凸台
│ │░░░░░░░│ │ ← 凹面 │░░░░░░░░░░░░░│
│ └───────┘ │ │░░░░░░░░░░░░░│
└─────────────┘ │ ┌───────┐ │
适用：易燃易爆 │ │ │ │ ← 槽
│ └───────┘ │
└─────────────┘
适用：高压+高危介质
【图 2】4 类密封面形式（FF/RF/MFM/TG）
Insufficient sealing surface hardness will lead to gasket compression deformation, sealing failure.TA2 sealing surface hardness recommendation ≥180HV(Same as 316L).
Sealing surface Ra 1.6μm causes leakage.Must be Ra≤0.8μmAbrasive paste progressive polishing.
After welding, butt welding flange and pipe must be annealed to eliminate stress (550-600℃ vacuum annealing）。Unannealed welds crack under corrosive conditions.
Flatness 0.05%DN will cause uneven sealing.Must be ≤0.05%DNAvoid titanium wire drawing.
Bolt hole position deviation ±0.5mm will lead to bolt installation failure, flange deformation after forced installation.Must have hole position tolerance ±0.5mm。
Purchasing Tips:Titanium flange identification: ① quality assurance certificate marking furnace batch + standard number + mechanical properties (TA2 tensile ≥370 MPa yield ≥275 MPa);(2) Ti + Mo/Ni/Pd peak position measured by XRF (only TA9 contains Pd, TA10 contains Mo+Ni);③ sealing surface hardness ≥180HV (measured);④100% PT Penetration Test Report.
Features:Drawing butt-welding flange PN ≥ 2.5 MPa, supplier report plate flange.
Consequences:Weld cracking and leakage under high pressure condition.
Features:Drawing TA 10 with crevice condition, supplier quote TA 2.
Consequences:Crevice corrosion condition 1-2 years perforation.
Features:The hardness of annealed TA2 is only 150-170HV, not up to 180HV.
Consequences:Gasket pressure deformation, seal failure.
Features:Titanium ring 2mm when 4mm reported.
Consequences:Titanium ring premature corrosion failure.
Features:Leakage PT penetration test or RT ray test report when flange enters factory.
Consequences:Forgings crack undetected, leakage failure after 1-2 years of operation.
Key Tips:Titanium flange procurement must be clear: ① brand + ② structure (PL/WN/Th/LJ)+ ③PN/DN + ④ sealing surface form (FF/RF/MFM/TG)+ ④ sealing surface hardness ≥180HV.Anything less could be a step in the hole.
Titanium flange in oxygen-containing Cl (wet chlorine, seawater), reducing acid (dilute H ˇ SO, HCl), medicine/food and other non-metal ion pollution conditions must be high;Stainless steel flange can only be used in ordinary steam, clean water, low Cl medium.Titanium Flanges are 5-8 times more expensive than stainless steel, but their life is 3-10 times longer.
PN≤1.6 MPa + normal temperature → plate type;PN≥2.5 MPa + high temperature → butt welding (neck forging, high strength).
DN≥600 large-caliber + cost reduction scenario.Titanium ring + steel flange loose sleeve structure, cost reduction of 25%, but the applicable pressure ≤1.6 MPa.
vital。Insufficient hardness → gasket deformation → seal failure.TA2 sealing surface hardness ≥180HV is the bottom line (measured).
After forging must be annealed (700-790℃ × 1-2h).After butt welding flange must be vacuum annealing (550-600℃).
Calculate kg according to "weight = π × (DN/2)² × δ × density 4.5," and then calculate kg according to material coefficient × unit price/kg + processing cost.DN100 TA2 butt welding about 0.5-1 kg × 130-180 yuan/kg + processing fee = 280-380 yuan/piece.
Quality assurance certificate marking batch + standard number + mechanical properties (TA2 tensile ≥ 370MPa yield ≥ 275MPa elongation ≥22%);XRF determination of Ti + Pd peak position (TA9 only contains Pd);Sealing surface hardness ≥180HV;100% PT test report.
GB/T 9112 + 9113 + 9124 is the basic national standard;HG/T 20592 is a standard of Ministry of Chemical Industry (PN series);ASME B16.5 is an American Standard (Class Series).ASME double-check is added for export.
| a particular year | Domestic titanium flange market (100 million yuan) | annual growth rate |
|---|---|---|
| 2024 | 6.5 | - |
| 2026E | 8.8 | 17% |
| 2028E | 12.5 | 19% |
| 2030E | 17.8 | 23% |
Although the flange is small, it is complete.It compresses the four things of "bearing + sealing + connection + maintenance" into a pair of flanges.Wrong flange selection, leakage of the whole equipment。
Select 5 numbers (DN), mark, construction, sealing surface), Manufacturing time control 5 degrees (sealing surface hardness, roughness, flatness, hole tolerance, PT detection coverage), Check 5 surfaces (external surface) during acceptance, internal surface, sealing face, bolt hole, a weld seam).
Author: Titanium non-standard technical number| Shaanxi Qianyi Tuoda Technology Co., Ltd.(Baoji·China Titanium Valley)
Keywords:Titanium flange, TA2 flange, TA10 flange, titanium butt welding flange,Titanium PlateType flange, titanium loose sleeve flange, flange selection, flange sealing surface, HG/T 20592, ASME B16.5, titanium metal information
Label:#Titanium flange #TA2 flange #TA10 flange #Titanium butt welding flange #Titanium PlateType flange #Titanium loose sleeve flange #Flange selection #Titanium information
Contact Person: Wang Xiaoning
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