Products Features

Excellent Oxidation and Reduction Resistance

High chromium content (14.0-18.0%) ensures the formation of a dense passivation film in oxidizing media (such as nitric acid, acids containing Fe³⁺/Cu²⁺). High molybdenum content (14.0-17.0%) provides excellent resistance to uniform corrosion in reducing media (such as hydrochloric acid, dilute sulfuric acid). This 'chromium + molybdenum' dual-core design enables it to handle complex service conditions ranging from strongly oxidizing to strongly reducing.

Exceptional Resistance to Pitting, Crevice Corrosion, and Stress Corrosion Cracking

The synergistic effect of high chromium and molybdenum content provides extremely high resistance to pitting and crevice corrosion (PREN ≥ 50) in chloride-containing environments, with excellent resistance to chloride-induced stress corrosion cracking, outperforming most austenitic stainless steels.

Superior Thermal Stability and Sensitization Resistance

Ultra-low carbon (≤0.015%), very low silicon (≤0.08%), strictly limited iron content (≤3.0%), combined with titanium stabilization (Ti ≤0.70%), ensure excellent microstructural stability in the medium-to-high temperature range of 650-1040°C. No brittle σ-phase or μ-phase precipitates form upon prolonged exposure to this temperature range. Even in the heat-affected zone after welding, its corrosion resistance remains almost unaffected, eliminating the need for post-weld heat treatment. This is the most distinctive feature distinguishing C-4 from the early C-276 alloy.

Good Formability and Weldability

It can be cold or hot formed using conventional processes, with a recommended hot working temperature range of 950-1200°C. It has good weldability (GTAW/TIG, GMAW/MIG, SMAW, etc.). It is recommended to use ERNiCrMo-7 filler wire (AWS A5.14 standard), with interpass temperature controlled at ≤150°C. Post-weld solution treatment is not required after welding, and it can be directly used in corrosive service conditions.

Technical Specifications

Chemical Composition

Element	Standard Requirements	Notes
Ni	Remaining quantity(≥65.0%)	Matrix elements that ensure the stability of face-centered cubic austenitic structure and provide excellent resistance to stress corrosion cracking
Cr	14.0 - 18.0%	Provides antioxidant and corrosion-resistant properties, which are key elements in forming a dense passivation film
Fe	≤ 3.0%	Strictly control at a low level to prevent the formation of harmful intermetallic phases
Mo	14.0 - 17.0%	Significantly improve resistance to corrosion by reducing acids, pitting corrosion, and crevice corrosion
Co	≤ 2.0%	Strict control to reduce the impact of impurities
Ti	≤ 0.70%	Stabilizing elements that preferentially combine with carbon to form TiC, eliminating intergranular corrosion sensitivity
C	≤ 0.015%	Ultra-low carbon content, preventing intergranular corrosion and eliminating the risk of carbide precipitation
Mn	≤ 1.0%	Deoxidizer, improve hot working properties
Si	≤ 0.08%	Extremely low silicon content to prevent intergranular corrosion tendency
P	≤ 0.030%	Impurity elements
S	≤ 0.030%	Prevent hot brittleness

Physical Properties

Property	Value/Range	Test Conditions
Density	8.64 g/cm³	Room temperature (20°C)
Melting Point	1335 - 1380°C	-
Coefficient of Thermal Expansion (20-100°C)	11.2 × 10⁻⁶ /K	-
Coefficient of thermal expansion (20-300°C)	11.8 × 10⁻⁶ /K	-
Elastic modulus (Young's modulus)	210 GPa	Room temperature
Thermal conductivity (20°C)	10.1 W/(m·K)	-
Resistivity	1.23 - 1.27 µΩ·m	Room temperature

Mechanical Properties (Annealed Condition, Typical Values)

Property	Typical Value	Specification
Tensile Strength	≥ 690 MPa	ASTM B574 / B575
Yield Strength	≥ 310 MPa	ASTM B574 / B575
Elongation	≥ 40%	ASTM B574 / B575
Hardness	≤ 100 HRB(or ≤ 220 HB)	-

High-temperature performance

Antioxidant Performance:

This alloy maintains structural and mechanical stability when used long-term below 600°C. It can withstand oxidizing atmospheres at high temperatures up to 800°C in the short term. However, for long-term use, it is recommended not to exceed 400°C to avoid embrittlement caused by precipitation of σ-phase and μ-phase.

Thermal Stability: C-4 is one of the materials with the most excellent microstructural stability among Ni-Cr-Mo alloys. When exposed long-term to the medium-to-high temperature range of 650-1040°C, it does not exhibit harmful intermetallic phase precipitation. Its weld heat-affected zone has good resistance to intergranular corrosion, allowing direct use in the as-welded condition. This characteristic significantly differentiates it from the earlier C-276 alloy: C-276 requires only about 3 minutes of sensitization time in the same temperature range, whereas C-4 requires over 2 hours.

Pitting Resistance Equivalent (PREN): PREN = %Cr + 3.3×%Mo + 16×%N ≈ 50-76 (depending on nitrogen content), which is much higher than 316L (≈25) and 904L (≈35). It exhibits excellent resistance to pitting and crevice corrosion in chloride-containing environments.

Critical Pitting Temperature (CPT): In 6% FeCl₃ solution (ASTM G48 standard), CPT ≥ 65°C, outperforming most austenitic stainless steels.

Applicable Media:

Chloride-containing seawater, saltwater, brines

Sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, and organic acids

Wet flue gas desulfurization (FGD) slurry

Oxidizing-reducing mixed acids

Paper bleaching solutions (chlorine, chlorine dioxide)

High-temperature and high-pressure water (nuclear power secondary circuit)

Acidic gas environments containing H₂S/CO₂

Note: The alloy shows good resistance to nitric acid with concentration ≤70% (below 50°C) and to acidic solutions containing oxidizing ions such as Fe³⁺ and Cu²⁺. However, it is not recommended for long-term use in strongly oxidizing environments (e.g., hot concentrated nitric acid, wet chlorine gas).

Hastelloy C-4 is specifically designed for harsh corrosive environments at moderate to low temperatures and is recommended for use in the following areas:

Application Fields

Chemical and Petrochemical Industries: Reactors, distillation columns, heat exchangers, piping, and valves handling sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and halide-containing media. Particularly suitable for organic acid production facilities such as acetic acid, acetic anhydride, and acrylic acid.
Flue Gas Desulfurization (FGD): Absorber spray layers, reheaters, wet gas fans, and agitators, resisting severe corrosion from high concentrations of chloride ions and sulfurous/sulfuric acids in desulfurization slurry.
Acetic Acid and Pesticide Production: Acetic acid/acetic anhydride reactors, distillation columns, and synthesis equipment for chlorine/chlorine-containing pesticide intermediates.
Pharmaceutical and Fine Chemicals: Multi-functional production equipment requiring high purity and resistance to various chemicals. Facilities for active substance preparation and drug synthesis.
Paper Industry: Digesters and bleaching equipment, resistant to corrosion from chlorine and chlorine dioxide-based bleaching solutions.
Oil and Gas: Pipelines and platform equipment in sour gas fields containing H₂S, CO₂, and Cl⁻. Complies with NACE MR0175 (ISO 15156-3) standards.
Environmental Engineering: Waste incineration flue gas purification equipment, wastewater treatment evaporators, waste acid/waste liquid evaporators, and reaction vessels.
Marine Engineering and Seawater Desalination: Seawater cooling pipelines, heat exchangers, pumps, valves, and desalination plants, resisting corrosion from high salinity and microorganisms.
Salt and Salt Chemicals: Evaporators, crystallizers, and salt slurry pumps, suitable for process environments with high chloride concentrations.
Titanium Dioxide Production (Chloride Process): Critical corrosion components in chloride process TiO₂ production facilities.

Delivery and Customization

We offer flexible and reliable supply chain solutions to ensure you receive Hastelloy C-4 materials that perfectly match your project requirements.

Form	Sheet/Plate	Bar/Rod	Seamless Pipe	Strip/Sheet Coil	Wire/Wire Rod
Conventional Range	Thickness: 0.5 - 100 mm Width: ≤ 1500 mm Length: Customizable	Diameter Φ6-500mm	Outer diameter Φ10-300mm	Thickness: 0.1 – 3.0 mm Width: 10 – 600 mm	Diameter Φ0.5-10mm
Customization Capability	Special thick/thin rolling, ultra-wide plates; special surface treatment, fixed-length cutting	Large-sized forged bars (up to Φ800 mm), special-shaped bars, and various heat treatment conditions	Large-diameter thick-walled pipes, special alloy composition; Pipe end processing (beveling, fixed length)	Different hardness conditions, special heat treatments (stabilization treatment, grain size control), acid-washed surfaces, electrolytic polishing, coatings, or special protective films	Special surface treatment, precision drawing

Why Choose Us? - Reliable engineering technology. Dependable delivery.

We are not just a supplier, but a trusted materials partner for you in China.

Vertically Integrated Production

Own 20,000㎡ facility with 10+ automated lines (8,000+ tons/year). In-house tooling & die center enables rapid customization and effective cost control - no middleman markup.

Strict Quality Control at Every Stage

Full traceability across key QC checkpoints throughout production. 100% compliant with ASTM/ASME, EN, and GB standards. Material test reports available with every shipment.

Reliable Delivery & Export Packaging

10+ years exporting to Europe, North America, Southeast Asia & Middle East with waterproof and anti-rust protection, combined with flexible shipping options ensures safe and on-time arrival.

Sample Validation Before Mass Production

We provide free samples for quality verification, allowing you to place bulk orders only after approval. We ensure consistency from sample to mass production by accurate dimensional measurement and transparent manufacturing.

FAQ

Q: What are the main advantages of Hastelloy C-4?

Q: What kind of heat treatment does Hastelloy C-4 require?

Q: What is the maximum service temperature?

Q: What is the difference between it and Hastelloy C-276?

Comparison Items	Hastelloy C-4	Hastelloy C-276
Core Composition	Nickel-Chromium-Molybdenum (Ni-Cr-Mo) Chromium: 14.0-18.0% Molybdenum: 14.0-17.0% Iron: ≤3.0% No tungsten; Titanium ≤0.70% Carbon ≤0.015%	Nickel-Chromium-Molybdenum (Ni-Cr-Mo) Cr: 14.5-16.5% Mo: 15-17% Fe: 4-7% Contains ~4% W, no Ti C ≤0.01%
Core Advantages	• Exceptional thermal stability - with extremely low tendency for harmful phase precipitation in the high-temperature range of 650–1040°C • No post-weld heat treatment required after welding; stable intergranular corrosion resistance in the welded condition • Ultra-low carbon + ultra-low silicon + titanium stabilization design to eliminate intergranular corrosion sensitivity	• A broad industrial application base with decades of use • Excellent overall corrosion resistance • Slightly better uniform corrosion performance than C-4 in strongly reducing acids (such as concentrated hydrochloric acid) • Relatively low cost
Selection Recommendations	It is recommended to prioritize welding equipment and high-temperature service conditions that are sensitive to thermal history: • Large-scale equipment requiring multiple welds or thermal processing • Thick-walled vessels and heat exchangers • Service conditions subjected to long-term operation within the 650-1040°C temperature range or frequent welding thermal cycles • Manufacturing of equipment that can be used directly after welding without requiring solution treatment • High-end application areas such as acetic acid/acetic anhydride production, flue gas desulfurization, and pharmaceuticals	Recommended for general corrosive environments: • General chemical process equipment • Seawater piping (non-extreme severe conditions) • Strongly reducing acid (e.g., high-concentration hydrochloric acid) applications • Applications with low thermal stability requirements • Cost-sensitive projects