Hastelloy C4 Flanges

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Hastelloy C4 Flanges Technical Specifications

Feature	Details
Specifications	ASTM B564 / ASME SB564 / DIN 17744
Grade	UNS N06455 (Hastelloy C4, Alloy C4)
Material Designation	Nickel-Chromium-Molybdenum Alloy (Ni-Cr-Mo)
UNS Number	N06455
Werkstoff Number	2.4610
Dimensional Standards	ANSI/ASME B16.5, B16.47 Series A & B, B16.48, MSS SP-44
Size Range	1/2" (15 NB) to 60" (1500 NB)
Pressure Class	150#, 300#, 400#, 600#, 900#, 1500#, 2500# (B16.5); 75#, 150#, 300#, 400#, 600#, 900# (B16.47)
Flange Types	Weld Neck, Slip-On, Blind, Socket Weld, Lap Joint, Threaded, Orifice, Long Weld Neck, Reducing
Flange Face	Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Male & Female, Tongue & Groove
Manufacturing Type	Hot Forged
Microstructure	Austenitic (FCC) Solid Solution (Solution Annealed)
Heat Treatment	Solution Annealed at 1175-1230-C + Rapid Water Quench (Mandatory)
Testing	Tensile, Hardness, Impact, PMI, Ferrite Detection, Ultrasonic
Inspection	Third Party Inspection by TUV, SGS, Bureau Veritas, Lloyd's, DNV GL, BV, ABS
Certifications	EN 10204 3.1B MTC, PED 2014/68/EU, CE Marked, ASME B31.3

Hastelloy C4 Equivalent Grades

STANDARD	USA	GERMANY	EUROPE	JAPAN	UK	CHINA
Hastelloy C4	UNS N06455	2.4610	2.4610	-	-	-
	ASTM B564 N06455	NiMo16Cr16Ti	NiMo16Cr16Ti
	Alloy C4	W.Nr. 2.4610
	Hastelloy C-4

Hastelloy C4 Chemical Composition

Mechanical Properties of Hastelloy C4 Flanges

Property	Requirement (Solution Annealed)	Testing Standard
Tensile Strength	785 MPa (114 ksi) minimum	ASTM E8
Yield Strength (0.2% offset)	400 MPa (58 ksi) minimum	ASTM E8
Elongation in 2"	40% minimum	ASTM E8
Hardness (Brinell)	180-230 HB (typical)	ASTM E10
Hardness (Rockwell B)	85-92 HRB (typical)	ASTM E18
Charpy V-Notch Impact	Excellent toughness	ASTM E23
Density	8.64 g/cm- (0.312 lb/in-)	-

Hastelloy C4 Flange Dimensions & Pressure Rating Chart

Pressure-Temperature Ratings for Hastelloy C4 Flanges (ASTM B564 N06455)

Temperature -F (-C)	Class 150	Class 300	Class 600	Class 900	Class 1500	Class 2500
-20 to 100 (-29 to 38)	285 psi	740 psi	1480 psi	2220 psi	3705 psi	6170 psi
200 (93)	260 psi	675 psi	1350 psi	2025 psi	3375 psi	5625 psi
400 (204)	233 psi	604 psi	1208 psi	1813 psi	3021 psi	5035 psi
600 (316)	205 psi	532 psi	1064 psi	1596 psi	2660 psi	4434 psi
800 (427)	177 psi	459 psi	919 psi	1378 psi	2297 psi	3828 psi
1000 (538)	150 psi	389 psi	778 psi	1167 psi	1945 psi	3242 psi
1200 (649)	122 psi	317 psi	634 psi	951 psi	1585 psi	2642 psi
1400 (760)	95 psi	246 psi	493 psi	740 psi	1233 psi	2055 psi

Types of Hastelloy C4 Flanges Available

Hastelloy C4 Orifice Flange

Hastelloy C4 Threaded Flange

Hastelloy C4 Reducing Flange

Hastelloy C4 Lap Joint Flange

Hastelloy C4 Long Weld Neck Flange

Hastelloy C4 Socket Weld Flange

Hastelloy C4 Weld Neck Flange

Hastelloy C4 Blind Flange

Hastelloy C4 Slip-On Flange

Standard Flange Sizes & Weight Chart

Hastelloy C4 Weld Neck Flange Dimensions (ANSI B16.5 - Class 600 Sample)

Is Hastelloy C4 Good Quality for Superior Thermal Stability and Weldability?

Yes, Hastelloy C4 (Alloy C4, UNS N06455) is known to be the most thermally stable of the Hastelloy C-family of alloys, specifically designed to offer enhanced ability to counteract grain boundary carbide precipitation and intergranular corrosion over the widest possible temperature range, notably in the very critical 650-1040degC (1200-1900degF) range where C-276 can suffer weld sensitization and loss of corrosion resistance in An improved version of C-276 introduced in 1970s by Haynes International as a sophisticated development over C-276, Hastelloy C4 overcomes the thermal stability drawbacks of previous C-alloys without sacrificing its good all-round corrosion behavior in oxidizing and reducing environments.

The very low carbon plus silicon content (blended maximum 0.08% with carbon maximum 0.015% and controlled titanium maximum 0.70) and reduced iron content (maximum 3.0% compared with 4-7 percentage in C-276) and regulated titanium content (maximum 0.70% versus 4-7 percentage in C-276) gives Hastelloy C4 outstanding performance in the weld heat-affected zone sensitization. This composition gives C4 a safe operating temperature in as-welded state over a wider range of high-temperature service than C-276 and avoids the use of a post-weld heat treatment of the material even after prolonged exposures to high temperature in the sensitization temperature range.

The proportions of molybdenum (14-17%) and chromium (14-18) are balanced giving C4 a great corrosion resistance in most conditions similar to that of C-276. The alloy exhibits excellent resistance to hot contaminated mineral acids such as sulfuric acid, hydrochloric acid, phosphoric acid and mixed acid. C4 is good in oxidizing chloride environments, but C22 would likely offer superior resistance in the harshest oxidizing environments.

Hastelloy C4 has critical benefits, such as better thermal behavior at the time of welding, fabrication, as well as in high-temperature service. The alloy has a wider range of temperature in which it will resist grain boundary carbide precipitation than C-276, and is suited to making use of thermal cycling, variations in process temperatures, or prolonged exposure to temperatures between 650-1040degC. The resulting thermal stability gives weld heat-affected areas the same corrosion resistance as the base metal despite subsequent thermal cycles or long-term exposure to high temperatures.

When used in hot contaminated sulfuric acid service, C4 is shown to be superior to C-276, especially in application where the acid has oxidizing contaminants or has temperature variations. The alloy is highly resistant to intergranular corrosion in boiling sulfuric acid levels when the sensitized C-276 could suffer increased grain boundary assault. C4 has good service in hydrochloric acid but special alloys, such as B2/B3, are used in the most demanding HCl applications.

C4 is a good corrosion inhibitor in oxidizing chloride solutions such as hypochlorite, chlorine dioxide and ferric/cupric chlorides albeit with C22 being superior under the most oxidising conditions. The thermal stability benefit of C4 is especially useful to chloride settings that undergo temperature cycling or a limited number of temperature excursions. The alloy is totally resistant to chloride stress corrosion cracking.

Hastelloy C4 is capable of sustaining good mechanical characteristics and anti-corrosion at high temperatures. The alloy exhibits high-temperature strength, which is better than that of C-276 because it has a higher content of molybdenum and an optimized composition. C4 is also good at oxidation resistance in oxidizing high-temperature atmospheres thus C4 is used in chemical reactors, heat exchangers and process equipment that can operate to 1040degC.

The thermal stability of C4 has been found to be of decisive benefit in critical applications such as chemical processing equipment that needs thermal cycling (reactors, heat exchangers, distillation columns), hot contaminated sulfuric acid service, pharmaceutical manufacturing equipment with clean-in-place thermal cycling, acetic acid production in high temperatures, operations in which the bleaching of pulp is performed with variations in temperature, high-temperature chloride service, applications where post-weld heat treatment is not feasible or not possible, and multipurpose chemical equipment that needs guaranteed weld integrity

The main factor to be considered with Hastelloy C4 is the cost and availability. C4 is usually pricier than C-276 and is not as popular with many fabricators having broad C4 knowledge as compared to the ubiquitous C-276. In those applications where C4 is not needed due to its higher thermal stability, C-276 is good with fewer costs. But where the critical use is needed, such as thermal cycling, hot contaminated acids, prolonged high-temperature operation, or where the weld sensitization of C-276 is a concern, the higher thermal stability and ability of C4 to resist grain boundary attack makes the high price worthwhile. C4 specification is according to the ASME B31.3 Process Piping Code of critical high temperature applications in corrosion.

Heat Treatment & Testing Requirements

Heat Treatment Requirements (Mandatory):

Process	Step / Parameter	Requirement	Remarks
Solution Annealing + Rapid Quenching	Solution Annealing Temperature	1175-1230-C (2150-2250-F)	Higher than C-276 due to thermal stability focus
	Holding Time	Adequate soaking	Based on section thickness, typically 30+ min
	Cooling After Annealing	Rapid water quench	Essential for single-phase austenitic structure
Critical Cooling Rate	Fast cooling through critical range	Maintains superior thermal stability advantage	Critical Requirement
Ferrite-free structure	Must be fully austenitic	Verify with ferrite detector

Testing & Inspection Requirements (Comprehensive):

Test / Inspection	Standard / Requirement	Acceptance / Remarks
Tensile Testing	ASTM E8	Yield = 58 ksi (400 MPa), Tensile = 114 ksi (785 MPa), Elongation = 40%
Hardness Testing	ASTM E10 / E18	Typical 180-230 HB (85-92 HRB)
Charpy Impact Testing	ASTM E23	Excellent toughness across temperature range
PMI Testing	Positive Material Identification	Ni (=65%), Mo (14-17%), Cr (14-18%), C (=0.015%), C+Si (=0.08%)
Ferrite Detection	Ferritescope / Magnetic test	Must be ferrite-free (0% ferrite)
Ultrasonic Testing	ASTM A388	Mandatory for critical high-temperature applications
Intergranular Corrosion Testing	ASTM A262 Practice C (optional)	Verification of resistance to grain boundary attack

Hastelloy C4 Nickel-Chromium-Molybdenum Alloy Flanges Price List 2026

Applications of Hastelloy C4 Flanges in Industry

The Hastelloy C4 Flanges are commonly used in many industrial applications, and some of the common industries are given below.

Chemical Processing

Hot contaminated sulfuric acid service, equipment with thermal cycling

High-Temperature Service

Reactors, heat exchangers, distillation columns operating 650-1040-C

Pharmaceutical

Manufacturing equipment with CIP thermal cycling, multipurpose reactors

Acetic Acid Production

Elevated temperature production and handling equipment

Pulp & Paper

Bleaching operations with temperature variations

Chloride Service

High-temperature chloride environments with thermal cycling

Welded Fabrications

Critical applications where post-weld heat treatment is impractical

Process Equipment

Applications requiring assured weld integrity across broad temperature ranges

Why Choose Hastelloy C4 Flanges from Metinox Overseas?

Metinox Overseas offers certified Hastelloy C4 (Alloy C4) nickel-chromium-molybdenum alloy flanges with selective solution annealing at 1175-1230degC, fast water quenching, and extensive testing with excellent service in raising thermal stability applications where resistance to grain boundary carbide precipitation and weld sensitization is needed. We have certified manufacturing plants of ISO 9001:2015 and PED. All flanges are manufactured with EN 10204 -3.1B Mill Test Certificates with full chemical analysis (tensile [?]114 ksi, yield [?]58 ksi, elongation [?]40%, C + Si 0.08%), full tensile properties (tensile [?]114 ksi, yield [?]58 ksi, elongation [?]40%), hardness confirmation, ferrite-free confirmation (0 percent ferrite) and PMI verification. Our technical department offers professional advice in C4 vs C-276 thermal stability comparison, hot contaminated acid services, thermal cycling, welding procedures (AWS A5.14 ERNiCrMo-13 filler metal) and compliance with ASME B31.3 to chemical processing plant needing thermal cycling, pharmaceutical manufacturers, thermal cycling, and high-temperature applications and critical welded fabrications globally.

Hastelloy C4 Flange Delivery Time & CIF Pricing by Country

Other Types of Hastelloy C4 Flanges

ASTM B564 N06455 Flanges, UNS N06455 Weld Neck Flanges, Hastelloy C4 Blind Flanges, Alloy C4 Thermal Stability Flanges, Hastelloy C4 Hot Acid Flanges, Alloy C4 As-Welded Condition Flanges.

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