Frequently Asked Questions

17-4 PH (also written 17/4PH, 17-4 stainless steel, or Type 630) is a precipitation-hardening martensitic stainless steel known for its excellent combination of high strength, hardness, and corrosion resistance.

Hastelloy, officially known as Hastelloy®, is a family of nickel-based superalloys known for their exceptional corrosion resistance and high-temperature strength.

Inconel is a family of nickel-chromium-based superalloys designed to withstand extreme conditions.

Monel is a family of nickel-copper alloys known for their excellent corrosion resistance and good mechanical strength.

Nimonic 80A is a nickel–chromium superalloy that was developed for use in high-temperature, high-stress environments.

S316 stainless steel (commonly known as Type 316 stainless steel) is an austenitic chromium-nickel stainless steel that contains molybdenum for enhanced corrosion resistance. It is one of the most widely used stainless steels for harsh or corrosive environments.

S410 stainless steel (commonly known as Type 410 stainless steel) is a martensitic stainless steel that offers a strong combination of high strength, hardness, and moderate corrosion resistance. It’s one of the earliest and most widely used martensitic grades, often chosen when mechanical strength and wear resistance are more important than maximum corrosion resistance.

Titanium is a lightweight, strong, and corrosion-resistant metal widely used in aerospace, chemical, medical, and marine industries.

C.S. Simmons Engineering are able to work with a wide range of materials, including Hastelloy, Inconel 718, Inconel 625, Monel K500, Monel K400, Ni Hard, Nimonic 80A, Super Duplex and Titanium.

C.S. Simmons Engineering is able to provide a wide range of precision engineering services for the oil and gas industry, including, but not limited to CNC Machining, Prototype Machining, Reverse Engineering, Castings Machining, Tooling and Welding.

C.S. Simmons Engineering offers a comprehensive range of precision engineering services for the renewable energy industry, including CNC machining, prototype machining, reverse engineering, casting machining, tooling, and welding.

C.S. Simmons Engineering is able to provide a wide range of precision engineering services for the oil and gas industry, including, but not limited to CNC Machining, Prototype Machining, Reverse Engineering, Castings Machining, Tooling and Welding.

C.S. Simmons Engineering is able to provide a wide range of precision engineering services for the oil and gas industry, including, but not limited to CNC Machining, Prototype Machining, Reverse Engineering, Castings Machining, Tooling and Welding.

C.S. Simmons Engineering offers a comprehensive range of precision engineering services for the renewable energy industry, including CNC machining, prototype machining, reverse engineering, casting machining, tooling, and welding.

C.S. Simmons Engineering offers a comprehensive range of precision engineering services for the renewable energy industry, including CNC machining, prototype machining, reverse engineering, casting machining, tooling, and welding.

We deliver a broad spectrum of precision engineering services for the oil subsea industry, covering CNC machining, prototype work, reverse engineering, casting machining, tooling, and welding

1. By Product Form

17-4 PH stainless steel is produced in a wide range of physical forms depending on how it’s going to be used.
You can find it as bars, rods, plates, sheets, strips, forgings, and castings, and even as powder for additive manufacturing (3D printing).

• Bars and rods are the most common and are used for shafts, fasteners, and fittings.
• Plates and sheets are used for larger structures or machined parts.
• Forgings are chosen when very high strength and reliability are required, such as in aerospace or heavy machinery.
• Castings are used for complex shapes like valve bodies or pump housings, and are usually made under the designation CB7Cu-1.

2. By Heat Treatment (Aging Condition)

The term “PH” stands for precipitation hardening, which is how the material gains its strength. After being solution treated (called Condition A), 17-4 PH can be aged at various temperatures to achieve different combinations of strength and toughness.
Each heat treatment condition is given a code, such as H900 or H1150.

• Condition A means the material has only been solution treated and not yet hardened. It’s softer and easier to machine or form.
• H900 gives the highest strength but the least ductility (hardest condition).
• H925 and H1025 are slightly softer, offering a better balance between strength and toughness.
• H1075 and H1100 provide good overall toughness and are often used when impact resistance is needed.
• H1150 gives the best toughness and resistance to stress corrosion cracking but at the cost of lower strength.
• H1150M (the “modified” condition) is a double-aged process that maximizes stress corrosion cracking resistance for critical environments like marine or chemical processing.

There are several different variations of Hastelloy on the market, including:

• Hastelloy C-22
  Resistant to a wide range of oxidising and reducing chemicals, commonly used for chemical processing and pollution control.
• Hastelloy C-276
  Excellent resistance to strong oxidisers and many acids, commonly used for pulp and paper industry, as well as wastewater treatment.
• Hastelloy X
  Known for its high-temperature strength and oxidation resistance, most commonly used within the aerospace industry (jet engine components), and industrial furnaces.
• Hastelloy B-2
  Prized for its resistance to hydrochloric acid and other reducing agents, commonly used across a wide range of industries, from chemical reactors to pickling operations.

Inconel 625

• Composition: Ni-Cr-Mo-Nb alloy
• Properties: Excellent corrosion resistance (especially against chloride), high strength, good weldability

Inconel 718

• Composition: Ni-Cr-Fe alloy with Nb, Mo, Ti, Al
• Properties: High strength at very high temperatures, good fatigue and creep resistance

Inconel 825

• Composition: Ni-Cr-Fe-Mo alloy
• Properties: Excellent corrosion resistance, especially in acids and seawater

Monel 400

• Composition: ~67% Ni, 28–30% Cu, small amounts of Fe, Mn, C
• Properties: Excellent corrosion resistance in seawater and chemical environments, good mechanical strength

2. Monel K-500

• Composition: Similar to Monel 400, but with aluminum and titanium additions
• Properties: Higher strength and hardness due to age-hardening capability, retains corrosion resistance

3. Monel R-405

• Composition: Modified version for improved corrosion resistance in acidic environments
• Properties: Resistant to stress corrosion cracking and high-temperature corrosion

Nimonic 80A is a stand alone alloy but can be supplied in several heat treatment conditions to optimize its mechanical properties for different applications:

• Solution-annealed: easy to machine/form.
• Age-hardened: has a high strength at elevated temperatures.
• Custom: optimised for specific service requirements.

1. 316 (Standard Grade)

• The basic version of Type 316 stainless steel.
• Composition: ~16–18% Cr, 10–14% Ni, 2–3% Mo.
• Properties: Excellent corrosion and oxidation resistance, good formability and weldability.
• Uses: Marine parts, chemical processing equipment, and food-grade applications.

2. 316L (Low Carbon)

• The “L” stands for Low Carbon (≤0.03% C).
• Advantage: Lower carbon content reduces carbide precipitation during welding, improving corrosion resistance in welded structures.
• Uses: Pressure vessels, pharmaceutical equipment, and marine components that require extensive welding.

3. 316H (High Carbon)

• The “H” stands for High Carbon (0.04–0.10% C).
• Advantage: Higher carbon increases strength and creep resistance at elevated temperatures.
• Uses: High-temperature industrial applications like heat exchangers, boilers, and furnace parts.

1. 410 (Standard Grade)

• Base composition: ~11.5–13.5% Cr, 0.08–0.15% C.
• Features: General-purpose martensitic stainless steel with good strength, hardness, and moderate corrosion resistance.
• Uses: Cutlery, pump shafts, turbine blades, valve components, and fasteners.

2. 410S (Low Carbon Variant)

• Lower carbon content (≤0.08%) than standard 410.
• Improved weldability and toughness, but cannot be hardened by heat treatment as effectively.
• Better resistance to scaling and oxidation at high temperatures.
• Uses: Welded or formed parts, exhaust systems, and furnace components.

3. 410HT (Heat-Treated 410)

• Same chemical composition as standard 410 but supplied in a hardened and tempered condition.
• Offers high strength and wear resistance for ready-to-use mechanical parts.

Commercially Pure Titanium (CP-Ti)

• Grades: 1, 2, 3, and 4
• Characteristics:
  • Excellent corrosion resistance
  • Good ductility
  • Lower strength than alloys

Titanium Alloys

• Common Alloying Elements: Aluminum (Al), Vanadium (V), Molybdenum (Mo), Nickel (Ni)
• Popular Alloys:
  • Ti-6Al-4V (Grade 5) – Most widely used titanium alloy
    • High strength-to-weight ratio
    • Excellent corrosion resistance
    • Applications: Aerospace, subsea components, medical implants, defence
  • Ti-6Al-4V ELI (Grade 23) – Extra low interstitials
    • Better fracture toughness
    • Used in medical implants and high-performance aerospace parts
  • Ti-3Al-2.5V, Ti-6Al-2Sn-4Zr-2Mo, Ti-5Al-2.5Sn – Specialized alloys for high-temperature or high-strength applications