Hāʻule Hou? ʻO ke kumukūʻai huna o ke koho ʻana i ka pā lole hewa
Ua nānā ʻoe i kahi hydrocracker moku hāʻule ma hope o ʻekolu makahiki wale nō? Loaʻa ka pohā ʻino o ke koʻikoʻi o Chloride ma o ka uhi welded. Ua ʻoi aku ka bila hoʻoponopono i ke kumukūʻai hana mua. Ua noi ʻia ka titanium paʻa—a hiki i ka wā i hōʻailona ʻia ai ke kūʻai $2 miliona kumu kūʻai no ke kolamu 50 mika.
Hoʻomaka hou kēia hiʻohiʻona. Pili ka poʻe ʻenekinia i nā ʻāpana ʻōwili liʻiliʻi a i ʻole nā uhi weld lahilahi. ʻO ka hopena? Kiʻekiʻe corrosion rate, nā pani i hoʻolālā ʻole ʻia, a nalowale hana ʻana. ʻAʻole uku ke kumu kumu - ʻo ia ka ʻenehana paʻa hewa.
Titanium ʻaʻahu ʻia pā kila no ka hoʻomaʻemaʻe ʻaila hoʻoponopono i kēia. Hoʻokumu ka paʻa pahū i kahi paʻa metala me ka dilution ʻole. ʻAʻohe intermetallic palupalu. Bond shear strength exceeds 140 MPa. The steel backing delivers structural integrity at 60% less weight than solid titanium. But you need the right specification, the right fabrication procedure, and a qualified supplier.
This article delivers the data. ʻAʻohe fluff. Here is what the standards, test results, and operating experience show.
Why Solid Titanium Fails Economically. Why Weld Overlay Fails Technically.
The choice between solid titanium, weld overlay, and clad pāpaʻa is not academic. It determines whether your vessel lasts 20 years or 3.
| Mea waiwai / System | Pale ʻino | Bond Integrity | Thickness Limitation | Relative Cost (per m² for 25 mm mānoanoa holoʻokoʻa) |
|---|---|---|---|---|
| Titanium paʻa (Gr. 2) | Maikaʻi | N/A (homogeneous) | Unlimited, but heavy | 100% (baseline) |
| Weld Overlay (Titanium on steel) | Maikaʻi loa, but dilution at interface | 15–30% iron dilution weakens corrosion resistance | Cladding ≤ 5 mm typical; risk of dilution beyond 8 mm | 55-65% |
| Explosion-Bonded Titanium Clad Steel Plate | Maikaʻi (pure titanium layer) | True metallurgical bond; 0% dilution | Hoʻopili: 1.5–10 mm; Kākua: a hiki i 100+ mm | 40–55% |
ʻIkepili mai a 2023 aʻo ʻia e ka Materials Technology Institute (MTI) hōʻoia: ma ka lawelawe ʻawaʻawa hoʻohālike (5% H2S, 200°C, pH 3.5), weld overlay hōʻike localized corrosion ma ka interface ma hope 500 hola. Pahū-paʻa nā papa ʻaʻole hōʻike hoʻouka ma hope 2,000 hola.
ʻO ka hoʻopaʻapaʻa kumu kūʻai pololei. ʻO ka titanium paʻa Gr. 2 he $45-55 no ke kilo. ʻO ke kākoʻo kila he $1-2 no ke kilo. He moku koi 25 ʻO ka nui o ka manoanoa me ka titanium paʻa e ʻoi aku ka nui o ka pāpaʻi pahū me 5 mm titanium + 20 mm SA516 Gr. 70. He mea koʻikoʻi nō hoʻi ka ʻokoʻa kaumaha. ʻO nā moku māmā e hōʻemi i nā kumukūʻai kumu a maʻalahi i ka hāpai ʻana.
ʻO ka pā kila kila no ka hoʻomaʻemaʻe ʻaila ʻaʻole ia he kuʻikahi. ʻO ia ka ʻenehana maikaʻi loa.
Ke Kaʻina Hana Pahū: No ke aha ia e hana ai i ka paʻa metala ʻoi loa
Pahū pahū (kapa ʻia hoʻi ka wiliwili pahū) he kaʻina hana kuʻihao paʻa. ʻO ka pahu pahū i hoʻomalu ʻia e hoʻolalelale i ka cladder titanium i ka wikiwiki kiʻekiʻe ma luna o ke kākoʻo kila. Hoʻokumu ka hopena i kahi jet plasma e hoʻomaʻemaʻe i nā ʻili. Paʻa nā metala me ka hoʻoheheʻe ʻole.
He mea koʻikoʻi kēia. ʻAʻole like me ka weld overlay—kahi i hui ai ka titanium me ka hao a hana i nā intermetallics TiFe palupalu—ʻaʻole waiho ʻia kahi ʻāpana hoʻoheheʻe ʻana o ka pahū.. He maʻemaʻe ka interface, laina paʻa nalu.
Nā ʻāpana koʻikoʻi no ka hoʻomaʻemaʻe ʻana i nā noi:
- Ka ikaika shear: ≥ 140 MPa no ka ASTM B898. Hōʻoiaʻiʻo.
- Ka ho'āʻo kani kani: E ʻae ʻia no ka pae ASTM A578 1. ʻAʻohe wahi i hoʻokaʻawale ʻia ma mua o 75 mm ma kekahi ʻaoʻao.
- Mānoanoa pale: ʻO ka maʻamau 3 mm no ka hāʻawi ʻana i ka corrosion; a hiki i 10 mm no nā kaiapuni koʻikoʻi.
- Ke kila kila: SA516 Gr. 70, SA387 Gr. 11/22 (no ka lawelawe awaawa), a i ʻole ASTM A105 no nā lako.
No ke aha he mea nui ka ikaika o ka pilina? I loko o kahi reactor me ka holo kaʻa wela wela (hoʻomaka / pani), ʻokoʻa ka hoʻonui wela ma waena o ka titanium (8.5 µm/m·°C) a me ke kila (11.7 µm/m·°C) hoʻopuka i ke koʻikoʻi shear ma ka interface. Hāʻule ka paʻa nāwaliwali. ʻO nā pāpaʻi paʻa i hoʻopaʻa ʻia e ola mau tausani o nā pōʻai.
Ka hihia: Ua hoʻololi ʻia kahi mea hoʻomaʻemaʻe nui ma ka Hikina Waena i nā mea hoʻoheheʻe weld-overlay aahu me nā pā kila titanium i hoʻopaʻa ʻia i ka pahū. 2019. Ma hope 4 mau makahiki o ka hana me ke kalaiwa kiʻekiʻe-chloride, ʻaʻole i ʻike ʻia ka disbonding a i ʻole ka corrosion. Pono nā moku weld-overlay mua e hoʻoponopono hou ma hope 18 mahina.
Nā noi koʻikoʻi: Kahi i ʻoi aku ka maikaʻi o ka pā kila kila Titanium i ka hoʻomaʻemaʻe ʻana
ʻAʻole pono nā moku āpau i ka pale ʻana i ka titanium. Akā ke loaʻa nā chlorides i ke kahawai kaʻina, H2S, a i ʻole nā ʻakika organik i ka wela kiʻekiʻe, ʻO ka titanium wale nō ke koho kumu kūʻai.
| Mea lako | Nā Kūlana lawelawe | ʻO ke ʻano hāʻule ʻole me ka uhi ʻole ʻana o Titanium | ʻO ka hoʻonā kila kila kila |
|---|---|---|---|
| Nā Reactors Desulfurization (RDS/VRDS) | 350-425°C, 14 MPa, H₂S+H₂, nā chloride mai ka mea hoʻoheheʻe | ʻO ke koʻikoʻi sulfide (SSC) o ke kila kuhilihi; hoʻouka waika polythionic | No Gr. 2 pale ka pale ʻana i ka SSC a me ka waika polythionic; paʻa paʻa kila |
| Nā Kolu Māhele (Ka lewa) | luna: 150°C, HCl/H₂S; Malalo: 350°C, nā ʻakika naphthenic | ʻO ka ʻino HCl koʻikoʻi ma ka ʻāpana luna; naphthenic acid corrosion ma waena | ʻO ka uhi ʻana ma luna 1/3 o kolamu; 317L a i ʻole duplex no nā ʻāpana haʻahaʻa no ka nānā ʻana i ke kumukūʻai |
| Mea Hoʻololi Wela (Hānai/Effluent) | ʻO ka pūpū: 300°C, kaʻina hana chloride; Paipu: 200°C, wai hooluolu | ʻO ka pohā ʻinoʻino o ka chloride o ke kila kuhiliʻole austenitic | ʻO ka pepa paipu a me ke kahawai Titanium; nā paipu Ti paʻa; pūpū kila no ka hoʻokele waiwai |
| Nā Waʻa Waiwai | 400°C, 17 MPa, kiʻekiʻe H₂S, amonia, chloride | Ammonium bisulfide corrosion; ka hāʻina hydrogen-induced (HIC) i ke kila | No Gr. 12 ka uhi ʻana (ʻoi aku ke kūpaʻa i ka ʻinoʻino); kākoʻo kila i kūpono no NACE MR0175 |
Pono kēlā me kēia noi i kahi kikoʻī o ka papa cladding. No Gr. 2 kūpono no ka hapa nui o nā kaiapuni hoʻomaʻemaʻe. No Gr. 12 hoʻohui 0.3% Mo and 0.8% Ni to improve resistance to crevice corrosion in high-temperature chloride services. ASTM B898 covers both grades.
ASTM B898: The Standard You Must Know Before Procuring
ASTM B898 is the governing specification for titanium clad steel plate for petroleum refining. It defines everything you need to specify, kūpono, and inspect the product.
Key requirements under B898:
- Bond classification: Class 1 (shear strength ≥ 140 MPa, full bond) or Class 2 (shear strength ≥ 105 MPa, acceptable for non-critical services). For refining, always specify Class 1.
- Cladding thickness tolerance: ±0.5 mm for nominal thickness up to 5 mm; ±1.0 mm for 5–10 mm.
- Ultrasonic inspection: Per ASTM A578 Level 1 or Level 2. pae 1 is stricter (no individual unbonded area > 75 mm at the longest dimension).
- Hoʻāʻo ʻāhi: Four samples per plate (each end and center). Minimum average shear stress must meet class limit.
- Hoʻo piʻo: 180° bend without cracking.
- Chemical analysis: Cladding per ASTM B265 (Ti Grade 1, 2, 7, 12, etc.); backing per ASME SA-516, SA-387, etc.
Never accept a clad plate without a certified ASTM B898 report. Too many suppliers substitute roll-bonded material (weaker bond, no wavy interface) a i ʻole ka weld overlay (dilution issues). The standard prevents that.
Hana ʻia: Welding Procedures That Make or Break the Vessel
You can buy the finest titanium clad steel plate. If the welds are wrong, the vessel leaks within months.
Titanium reacts with oxygen, nitrogen, and hydrogen above 300°C. Weld areas must be shielded by inert gas (argon) until cooled below 250°C. Here is the proven sequence for field or shop welding of titanium clad steel plate for petroleum refining:
- Butter the steel side with a nickel-based alloy (e.g., ERNiCrMo-3) to seal the steel from hydrogen pickup during titanium welding.
- Weld the steel backing using approved filler (e.g., E7018 for SA516). Ensure complete penetration. Back-gouge the steel side to remove buttering before the final pass.
- Remove backing strip (if used). Clean the titanium surface. Do not grind with contaminated wheels—use dedicated stainless steel tools.
- Weld the titanium cladding using ERTi-2 filler for Grade 2, or ERTi-12 for Grade 12. Purge with argon (both sides). Use a trailing shield to protect the hot weld zone.
- Perform seal welds at the edges to prevent ingress of process fluids between cladding and backing.
- Inspect: Visual (blue color indicates contamination—reject), dye penetrant (all titanium weld surfaces), ultrasonic (for disbonding under weld HAZ), and leak test (helium).
Critical: Never weld titanium directly to carbon steel with a steel filler. The TiFe intermetallic is brittle and cracks immediately. Use a buttering layer or a nickel transition piece.
A qualified fabricator who knows these steps is rare. Insist on a Welding Procedure Specification (WPS) qualified per ASME Section IX with your exact material combination. Do not accept a generic procedure.
Sourcing: Five Questions to Ask Before You Place the Order
Sourcing titanium clad steel plate for petroleum refining from an ASTM composite panel exporter requires due diligence. Not all exporters are equal. Here is the checklist:
| Ninau | Why It Matters | Acceptable Answer |
|---|---|---|
| 1. Do you have ASTM B898 certification for Class 1 nā papa? | Ensures bond strength and testing protocols. | ʻAe, with recent certificate from an accredited lab. |
| 2. What is your ultrasonic testing capability? | You need 100% inspection per A578 Level 1. | In-house UT with automated scanning and C-scan record. |
| 3. Can you supply cladding thickness > 6 mm? | High-corrosion or abrasion-resistant services demand thicker cladding. | ʻAe, a hiki i 10 mm Ti on 100 mm kākoʻo. |
| 4. What backing steel grades do you offer for sour service? | NACE MR0175/ISO 15156 compliance is mandatory for H2S. | SA516 Gr. 70 with HIC test; SA387 Gr. 11/22. |
| 5. Do you provide weld trial support or field welding training? | Poor fabrication ruins the best plate. | ʻAe, we provide a welding guide and on-site support. |
Trust no one without sight of their quality manual, test reports, and at least one reference job in refining. The cost of a failed clad plate—lost production, hoʻoponopono, potential safety incident—far exceeds the 10–15% price difference between a qualified and unqualified supplier.
The Bottom Line: Cost Savings, Ka lōʻihi, and Data-Driven Choice
Carbon steel costs $1–2 per kg. Titanium costs $45–55 per kg. A 50-tonne reactor in solid titanium would cost $2.5 million just for the material. The same reactor built with titanium clad steel plate (5 mm Ti + 20 mm kila) koina $1.1 million—a 56% savings.
But the real metric is Total Cost of Ownership (TCO). A clad plate lasts 20+ years in sour service. Weld overlay lasts 5–10 years before localized corrosion at the dilution zone forces replacement. The TCO comparison is clear:
- Solid titanium: Ke kumu kūʻai kiʻekiʻe, mālama haʻahaʻa, but extreme weight requires reinforced foundations.
- Weld overlay: Medium initial cost, high maintenance (inspection, repair every 2-3 makahiki), risk of catastrophic failure.
- Explosion-bonded titanium clad steel: Lowest TCO due to long life, no corrosion under insulation, a me ka pono hana.
Industry data from a 2022 survey of 12 US refineries showed that facilities using explosion-bonded titanium clad steel for their high-chloride units experienced zero corrosion-related unplanned shutdowns in the 10-year survey period. Those using other cladding methods averaged 2.5 shutdowns per unit.
The trend is accelerating. As refineries process increasingly sour crude (higher sulfur, higher TAN), titanium clad steel plate for petroleum refining is becoming the default specification for new builds and revamps. The technology has proven itself for 30+ makahiki. It is mature. It is reliable. It is now cost-competitive.
Make your next specification easier. Download our free selection guide for titanium clad plates in refining service. Or better—call our applications engineering team. We will help you calculate the exact TCO for your vessel. No sales pitch. Just data.
Mea hoolako
ʻO Metal Plate 4U kahi mea hoʻolako pūʻulu metala composite honua & mea hana me ka ʻike nui i ka hāʻawi ʻana i ke kila kila kila kiʻekiʻe, nickel alloy, kila keleawe, a me nā pā kila titanium. Hoʻokuʻu aku ka hui i nā ʻāina he nui, e like me ka USA, Kanaka, ʻEulopa, UAE, ʻApelika Hema, etc. Ma ke ʻano he alakaʻi pahū i hoʻopaʻa ʻia i ka mea hoʻomohala pā, ʻO ka Metal Plate 4U ka luna o ka mākeke. Hāʻawi kā mākou hui hana ʻoihana i nā hāʻina kūpono e kōkua i ka hoʻomaikaʻi ʻana i ka pono o nā ʻoihana like ʻole, e like me na ipu kaomi, nā mea hoʻololi wela, hana moku, a me ka hana kemika, hana waiwai, a maʻalahi hoʻi i nā pilikia like ʻole. Inā ʻoe e ʻimi nei i nā panela metala composite a i ʻole nā papa lole bimetal, e ʻoluʻolu e hoʻokaʻaʻike mai iā mākou!