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Name: Shanghai Hangbo Alloy Group Co., Ltd.
Address: Shanghai, Shanghai, 201900, CN
Telephone: +86 15618279078

Practical metallurgy written for engineers and procurement teams. Each guide states the decision rule first, then the data that supports it, and ends with the questions buyers ask.

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Technical knowledge archive

2026-09-20 · 9 min read
Welding Inconel 625 to carbon steel: buttering, filler and control
How to make a sound dissimilar joint between Inconel 625 and carbon steel: buttering sequence, filler selection, dilution control, preheat and post weld heat treatment decisions, and…
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2026-09-19 · 9 min read
Heat numbers and mill test certificates: reading the paperwork properly
What a heat number identifies, what a mill test certificate to EN 10204 3.1 must contain, how to spot a weak certificate, and how to keep traceability intact from melt to installed…
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2026-09-18 · 8 min read
ASTM B564 explained: what the flange material specification actually covers
What ASTM B564 covers, which UNS numbers it includes, how it relates to ASME B16.5 and B16.47, and the supplementary requirements you should state when ordering nickel alloy…
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2026-09-17 · 8 min read
Positive material identification: the control that prevents mixed material
How positive material identification works, XRF versus optical emission spectroscopy, what each can and cannot detect, coverage levels to specify, and how to record results for an…
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2026-09-16 · 8 min read
Duplex 2205 flanges to ASTM A182 F51: what the grade actually delivers
Duplex 2205 flanges to ASTM A182 F51 and UNS S32205: composition, strength advantage over 316L, temperature limits, sigma phase risk and what to state on the purchase…
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2026-09-15 · 8 min read
ASTM B366 explained: the specification behind nickel alloy fittings
What ASTM B366 covers, how wrought fittings differ from forged ones, the WP and CR class designations, and the dimensional and marking standards that must accompany…
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2026-09-14 · 9 min read
Inconel 625 flanges to ASTM B564: properties, classes and ordering notes
Inconel 625 flanges to ASTM B564 and UNS N06625: chemistry, mechanical properties, ASME B16.5 class coverage, heat treatment, NDT scope and purchase order…
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2026-09-13 · 9 min read
Super duplex 2507 for subsea and high chloride piping
Super duplex 2507 composition, PREN, subsea and desalination performance, welding controls, impact testing and specification notes for flanges, fittings and seamless…
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2026-09-12 · 8 min read
Inconel 718 flanges and bolting: strength, hardness limits and sour service
Inconel 718 flanges and bolting to UNS N07718: age hardening response, strength versus 625, NACE MR0175 hardness limits, galling control and when 718 is the correct…
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2026-09-11 · 8 min read
Incoloy 825 for sulphuric and phosphoric acid piping
Incoloy 825 composition, acid resistance, temperature limits and specification notes for flanges, fittings and seamless tube in sulphuric, phosphoric and sour produced water…
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2026-09-10 · 8 min read
Flange facing types: raised face, flat face, ring joint and tongue and groove
How raised face, flat face, ring type joint, tongue and groove and male and female facings work, which gasket each needs, and how to choose the right facing for pressure, temperature and…
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2026-09-09 · 9 min read
Hastelloy C-276 flanges: the reference alloy for aggressive chemical duty
Hastelloy C-276 flanges and fittings to ASTM B564 and B366: composition, corrosion limits, thermal exposure risks, welding filler selection and what to state on the purchase…
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2026-09-09 · 9 min read
Welding duplex stainless flanges: keeping the phase balance
How to weld duplex and super duplex flanges without losing corrosion resistance or toughness: filler selection, heat input and interpass limits, shielding gas with nitrogen, and…
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2026-09-08 · 7 min read
Inconel 600 vs Inconel 625: which alloy for your piping?
Composition, corrosion resistance, strength and cost comparison of Inconel 600 and Inconel 625 for flanges and fittings, with clear guidance on where each alloy is the right…
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2026-09-07 · 9 min read
Titanium Grade 2 for seawater, chlorine and desalination piping
Why titanium Grade 2 is effectively immune to seawater corrosion, where it is used in desalination and chlor alkali plants, and the limits around velocity, crevices, dry chlorine and…
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2026-09-06 · 9 min read
ASME B16.5 pressure temperature ratings: how to read the tables
How ASME B16.5 pressure class, material group and temperature interact, what the rating actually means, how to interpolate, and the mistakes that cause an under rated flange to be…
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2026-09-05 · 8 min read
Inconel 601 and 617 for elevated temperature fittings and ducting
Inconel 601 and Inconel 617 for furnace, exhaust and reformer piping: oxidation limits, creep strength, thermal fatigue behaviour and how to specify flanges and fittings for hot…
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2026-09-05 · 8 min read
Crevice corrosion under gaskets and deposits: the hidden failure mode
Why crevice corrosion starts at gasket faces, under deposits and at tube joints, how it differs from pitting, and the design, material and maintenance measures that prevent…
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2026-09-04 · 8 min read
Monel 400 in seawater and hydrofluoric acid service
Monel 400 composition, seawater and hydrofluoric acid performance, velocity and erosion limits, galvanic considerations and specification notes for flanges and…
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2026-09-03 · 7 min read
MSS SP-25 marking: the cheapest traceability you will ever buy
What MSS SP-25 requires to be marked on flanges and fittings, why the heat number matters for lifecycle traceability, and how to specify marking so it survives painting, insulation and…
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2026-09-02 · 7 min read
Incoloy 800H vs 800HT: what the extra letters actually buy
The real difference between Incoloy 800H and 800HT: carbon content, titanium and aluminium limits, grain size requirement, allowable stresses and how to specify the correct variant for hot…
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2026-09-01 · 8 min read
Duplex 2205 vs 316L: the cost case, not just the corrosion case
A practical comparison of duplex 2205 and 316L for piping and flanges: strength, corrosion limits, wall thickness saving, fabrication cost and the conditions where 316L remains the correct…
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2026-08-31 · 8 min read
Welding titanium: shielding, contamination and why colour matters
Why titanium welds need primary, trailing and backing gas shielding, what weld colour tells you about contamination, how to control iron and interstitial pickup, and the examination steps…
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2026-08-30 · 7 min read
Inconel 690 for steam generator tubing and caustic service
Why Inconel 690 replaced Inconel 600 in steam generator tubing: stress corrosion cracking resistance, chromium content, thermal treatment and specification notes for seamless tube and…
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2026-08-29 · 7 min read
Long radius versus short radius elbows: what the difference costs you
The dimensional, pressure drop and erosion differences between long radius and short radius elbows to ASME B16.9, and how to choose for slurry, high velocity and space constrained…
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2026-08-28 · 7 min read
Incoloy 925 for sour oil and gas flanges and tubular components
Incoloy 925 composition, age hardening response, NACE MR0175 position and specification notes for sour wellhead, Christmas tree and downhole components in flanged…
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2026-08-28 · 8 min read
Erosion corrosion in elbows and tees: where velocity attacks first
How velocity, entrained solids and two phase flow remove the protective film at changes of direction, why elbows and tees fail first, and the material and layout measures that control…
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2026-08-27 · 7 min read
Concentric versus eccentric reducers: choosing by what settles out
The functional difference between concentric and eccentric reducers, why horizontal pump suction lines need eccentric reducers, how to specify flat on top or flat on bottom and the layout…
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2026-08-26 · 7 min read
Inconel X-750: the alloy behind high temperature fasteners and springs
Inconel X-750 composition, age hardening response, heat treatment conditions, relaxation resistance at temperature and practical guidance for fasteners, springs and retaining…
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2026-08-25 · 9 min read
NACE MR0175 / ISO 15156 requirements for flanges in sour service
What sour service compliance means for alloy flanges and fittings: hardness limits, heat treatment conditions, material listings, documentation and the questions to settle before…
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2026-08-24 · 7 min read
Incoloy A-286: high strength bolting for elevated temperature joints
Incoloy A-286 composition, ageing response, strength at temperature, galvanic considerations and specification notes for high strength studs, bolts and nuts on alloy flanged…
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2026-08-24 · 8 min read
Galvanic corrosion when nickel alloys meet carbon steel
How galvanic corrosion works in a flanged joint, why area ratio matters more than the alloy pair, and the isolation, coating and material measures that prevent the carbon steel from…
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2026-08-23 · 8 min read
Hydrostatic testing and non destructive examination of alloy fittings
What hydrostatic testing proves, how non destructive methods such as ultrasonic, dye penetrant and radiography apply to fittings and flanges, and how to specify an examination scope that is…
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2026-08-22 · 9 min read
Machining and welding Inconel 625 flanges: shop practice that works
Practical shop guidance for Inconel 625: tooling, cutting speeds, work hardening control, weld procedure essentials, filler selection and how to avoid the defects that cause…
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2026-08-21 · 8 min read
Pipe schedules and wall thickness: choosing the wall that the duty needs
How pipe schedules relate to wall thickness, why schedule number is not a strength measure, how corrosion allowance and mill tolerance affect the choice, and how to specify wall thickness…
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2026-08-20 · 7 min read
Hastelloy C-22 vs C-276: choosing between the two workhorse C alloys
Composition, PREN and service comparison of Hastelloy C-22 and C-276 for flanges and fittings, with guidance on oxidising versus reducing conditions, thermal stability and…
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2026-08-20 · 7 min read
Pickling, passivation and iron contamination control
Why free iron on the surface causes rust and pitting, how pickling and passivation differ, when each is required, and how to verify that a surface is clean without damaging…
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2026-08-19 · 8 min read
PREN and critical pitting temperature: use both, trust neither blindly
What the pitting resistance equivalent number does and does not tell you, how critical pitting temperature is measured, and how to use both when shortlisting alloys for chloride…
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2026-08-18 · 8 min read
Inconel 625 vs Hastelloy C-276: a selection method, not a preference
How to choose between Inconel 625 and Hastelloy C-276 using the actual stream chemistry, temperature and failure modes, with composition, PREN and cost boundary guidance for flanges and…
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2026-08-18 · 9 min read
Material selection for sour service: an H2S decision path
How to select materials for hydrogen sulphide service: the cracking mechanisms involved, the role of hardness and heat treatment, the usual alloy ladder and the information you need before…
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2026-08-17 · 7 min read
Post weld heat treatment of nickel alloys: when to specify and when to avoid
Why most nickel alloy welds need no post weld heat treatment, when stress relief and solution annealing are justified, the temperature ranges that must be avoided, and how to record the…
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2026-08-16 · 7 min read
Hastelloy B-2 and B-3: the hydrochloric acid specialists
Why Hastelloy B-2 and B-3 are used for hydrochloric acid: very high molybdenum, low chromium, thermal stability differences between the two grades and specification notes for flanges and…
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2026-08-15 · 8 min read
Inconel 718 vs Inconel 625 for flanges, fittings and bolting
Side by side comparison of Inconel 718 and Inconel 625 covering strength, corrosion resistance, heat treatment sensitivity, weldability, machinability and typical applications in flanged…
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2026-08-15 · 8 min read
Flange leak troubleshooting: a checklist that finds the real cause
A structured approach to diagnosing leaking alloy flanges: separating bolting, gasket, facing, alignment and material causes, with the checks to make before you blame the…
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2026-08-14 · 8 min read
ASME B16.47 large diameter flanges: series A versus series B
Differences between ASME B16.47 series A and series B large diameter flanges, their origins, dimensional consequences, bolting differences and how to specify the correct series for a…
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2026-08-13 · 7 min read
Solution annealing and sensitisation: what the heat treatment actually achieves
What solution annealing does, how sensitisation removes chromium from grain boundaries, which grades are at risk, and how to specify and verify a correct thermal…
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2026-08-12 · 9 min read
How to choose a flange material for corrosive service
A practical five-step method for selecting flange material in corrosive service: identify the fluid, rank the failure modes, shortlist alloys by PREN and temperature, then verify hardness,…
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2026-08-12 · 8 min read
Sigma phase in super duplex: how it forms and how to prevent it
What sigma phase is, the temperature range where it forms, why it removes toughness and corrosion resistance, how it is detected and the heat treatment and welding controls that prevent…
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2026-08-11 · 7 min read
ASTM A182 duplex flange grades: F51, F53 and F55 decoded
What the ASTM A182 F51, F53 and F55 designations mean, which UNS numbers they map to, the differences in chemistry and strength, and how to specify duplex and super duplex flanges…
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2026-08-10 · 8 min read
Inconel 625 weld overlay: the economical way to buy corrosion resistance
How Inconel 625 weld overlay and cladding work on carbon steel flanges and fittings: process options, dilution control, thickness, inspection and when solid alloy is still the better…
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2026-08-09 · 7 min read
Storage and handling of alloy flanges: protecting the investment
How to store, protect and handle stainless, duplex, nickel alloy and titanium flanges and fittings so that the sealing faces, markings and surface condition are not damaged before…
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2026-08-08 · 7 min read
316L, 316Ti and 317L: choosing within the molybdenum stainless family
Composition, sensitisation behaviour, PREN and service differences between 316L, 316Ti and 317L, with guidance on which to specify for welded flanges, fittings and…
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2026-08-06 · 7 min read
Monel K-500: age hardened strength with Monel corrosion resistance
Monel K-500 composition, ageing response, strength advantage over Monel 400, risks in stagnant seawater and specification notes for shafts, fasteners and high strength flanged…
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2026-08-04 · 8 min read
Titanium Grade 5 (Ti-6Al-4V) vs Grade 2: strength versus corrosion
Composition, strength, corrosion resistance, weldability and cost comparison of titanium Grade 5 and Grade 2 for flanges, fittings and pressure containing…
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2026-08-02 · 7 min read
Nickel 200 vs Nickel 201: the caustic service decision
Why Nickel 201 replaces Nickel 200 above about 315 C: carbon content, graphitisation risk, caustic resistance, mechanical limits and specification notes for flanges and seamless…
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2026-07-30 · 7 min read
904L stainless steel for sulphuric acid piping
Where 904L fits in sulphuric acid service: composition, concentration and temperature limits, comparison with 316L and duplex, and specification notes for flanges and…
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2026-07-28 · 8 min read
Inconel 625 vs 316L for marine piping: when the upgrade pays
Composition, PREN, strength and cost comparison of Inconel 625 against 316L in seawater service, with clear decision boundaries for when 316L is adequate, when duplex wins and when only 625…
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2026-07-26 · 7 min read
254SMO vs 904L: two different answers to chloride problems
Composition, PREN and critical pitting temperature comparison of 254SMO and 904L, with clear guidance on which super austenitic grade to specify for chloride, seawater and acid…
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2026-07-22 · 7 min read
Stabilised stainless steel: when 321 and 347 beat 304H and 316H
Why 321 and 347 are specified for elevated temperature and welded fabrication: titanium and niobium stabilisation, sensitisation resistance, service limits and specification…
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2026-07-18 · 7 min read
17-4PH and 15-5PH: precipitation hardening stainless for strength
Composition, heat treatment conditions, strength and toughness differences between 17-4PH and 15-5PH, with guidance on using precipitation hardening stainless for flanges and…
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2026-07-14 · 7 min read
310S and 253MA: austenitic grades for elevated temperature service
Oxidation limits, creep strength, thermal fatigue and specification guidance for 310S and 253MA in furnace, kiln and exhaust applications where austenitic stainless is preferred to nickel…
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2026-07-10 · 7 min read
How to read nickel alloy fitting markings (ASTM B366, ASME B16.9, MSS SP-25)
Decode the markings on nickel alloy butt weld fittings and flanges: manufacturer symbol, grade, schedule, size, heat number and standard, with worked examples and the mistakes to avoid on…
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2026-07-10 · 7 min read
Titanium Grade 7 and Grade 12: closing the crevice and reducing acid gaps
What palladium in Grade 7 and nickel molybdenum in Grade 12 add to commercially pure titanium, and when the premium is justified for hot brine, acidic chloride and reducing chemical…
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2026-06-25 · 7 min read
ASME B16.9 elbow dimensions explained: LR, SR, angles and tolerances
How ASME B16.9 elbow dimensions are derived, why long radius centre-to-end equals 1.5 x NPS, how to read the tolerance table and how to specify 3D and 5D bends for piggable…
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2026-06-05 · 7 min read
Duplex 2205 vs super duplex 2507: choosing the right duplex grade
Composition, PREN, strength and cost comparison of duplex 2205 against super duplex 2507, with decision guidance for subsea, desalination, seawater injection and chemical…
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2026-05-20 · 8 min read
Inconel 718 heat treatment explained: solution anneal and double ageing
Why Inconel 718 is solution annealed then double aged at 720 °C and 620 °C, what the gamma double prime phase actually does, and how condition affects machining, welding and API 6A…
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