Products

Home Stainless Steel AISI440C-1.4125-UNS S44004-X105CrMo17-SUS440C

AISI440C-1.4125-UNS S44004-X105CrMo17-SUS440C

AISI 440C is a high-carbon martensitic stainless steel with excellent wear resistance, high strength, and good corrosion resistance. After heat treatment, this material can achieve high hardness and excellent mechanical properties while maintaining a certain level of corrosion resistance. Therefore, it is widely used in industrial and precision component applications where high wear resistance and strength are required.

DIN EN 10088-1：
Stainless steels - Part 1: List of stainless steels
ASTM A276：
Standard Specification for Stainless Steel Bars and Shapes
ASTM F899：
Standard Specification for Wrought Stainless Steels for Surgical Instruments

Get a Free Sample

Chemical Composition

Element	CA	Mn	P	SA	Si	Cr	Mo	Fe
Content (%)	0.95-1.20	≤1.00	≤0.04	≤0.030	≤1.00	16.00-18.00	≤0.75	Balance

Heat Treatment Conditions

Condition	Heating Temperature	Hardness
Annealed	/	≤285（HBW）
Quenched and tempered	Q 1900℉/1038℃ T 300℉/149℃+	≥60（HRC）

Supply Forms

Available Form	Size Range	Surface Finish	Length (Customizable)	Tolerance (Customizable)	Delivery Condition
Plate	T0.5-T200.0mm	Milled / Bright	L:200/250/300W:200/300/500/1000	-0.0/+1.0mm	Annealed
Bar	φ1.0-φ200.0mm	Ground / Precision Polished	3M/PCS	h6-h9	Annealed
Wire	φ1.0-φ3.0mm	Ground / Precision Polished	1M/PCS	h6-h9	Annealed
Tube	OD：1.0-10.0mmID:0.08mm-2.0mm	Ground / Precision Polished	3M/PCS	h6-h9	Annealed

Datasheet

Additional Info

A Brief History of 17‑4 PH Stainless Steel

17-4 PH Stainless Steel, also known as UNS S17400, AISI 630, Type 630, or 1.4542 stainless steel, is a precipitation-hardening martensitic stainless steel developed for applications that require a balanced combination of high strength, good corrosion resistance, and reliable mechanical performance. Since its introduction in the mid-20th century, 17-4 PH has become one of the most widely used stainless steel grades in demanding engineering environments.

Unlike conventional stainless steels that mainly focus on corrosion resistance, 17-4 PH was designed to offer both stainless steel corrosion performance and significantly improved strength after aging treatment. This unique combination has made it an important material choice for aerospace, medical, oil and gas, precision machinery, and industrial manufacturing applications.

Through its copper-containing precipitation-hardening system, 17-4 PH stainless steel can achieve high tensile strength, good hardness, and stable dimensional performance while maintaining practical corrosion resistance in many service environments. As a result, it has remained a reliable material for components where strength, accuracy, and durability are all required.

How 17‑4 PH Was Developed

17-4 PH stainless steel was developed to meet the growing need for a material that could be processed in a relatively workable condition and then strengthened through controlled heat treatment. In the solution-annealed condition, commonly referred to as Condition A, the material can be machined or formed more easily before final aging treatment is applied.

The alloy design is based on a careful balance of chromium, nickel, copper, and niobium. Chromium provides stainless steel corrosion resistance, nickel contributes to toughness and structural stability, while copper and niobium support the precipitation-hardening response during aging. This controlled metallurgical design allows 17-4 PH to reach different strength levels depending on the selected heat treatment condition.

Common aging conditions include H900, H1025, H1075, H1100, and H1150. Each condition offers a different balance of tensile strength, hardness, toughness, and ductility. This flexibility allows engineers and manufacturers to select the most suitable condition according to the final application, whether the priority is maximum strength, improved toughness, better machinability, or long-term dimensional stability.

Early Applications of 17‑4PH

In its early use, 17-4 PH stainless steel was quickly adopted in industries where traditional stainless steels could not provide enough strength and alloy steels could not offer sufficient corrosion resistance. Aerospace, defense, and high-performance industrial sectors were among the first to recognize the value of this precipitation-hardening stainless steel.

The material was used for aircraft fittings, shafts, fasteners, valve parts, structural components, and precision-machined hardware. Its ability to obtain high strength through heat treatment, while maintaining better corrosion resistance than many carbon and low-alloy steels, made it suitable for parts exposed to mechanical stress and moderately corrosive environments.

Another important advantage of 17-4 PH was its predictable heat-treatment response. Manufacturers could process components with relatively consistent mechanical properties and dimensional stability, which was especially important for precision parts requiring tight tolerances. This helped expand the use of 17-4 PH stainless steel bar and machined components in both aerospace and industrial production.

How 17‑4 PH Is Used Today

Today, 17-4 PH Stainless Steel remains a highly specified precipitation-hardening stainless steel for applications where strength, corrosion resistance, machinability, and dimensional accuracy must work together. It is commonly supplied in bars, rods, plates, sheets, tubes, pipes, wires, strips, and precision-processed forms to meet different manufacturing requirements.

Common applications include:

Aerospace: structural fittings, aircraft components, shafts, fasteners, high-strength connectors

Medical: surgical instruments, orthopedic tools, medical device components, precision mechanical parts

Oil & Gas: valve components, pump shafts, connectors, downhole and pressure-related parts

Industrial Manufacturing: gears, pins, tooling parts, wear-resistant components, precision machined parts

Chemical & Energy Equipment: reactor components, agitation shafts, turbine-related parts, high-strength structural elements

17-4 PH stainless steel is widely used in both solution-annealed and aged conditions. Solution-annealed material is suitable for further machining or processing, while aged conditions provide enhanced strength and hardness for load-bearing or wear-critical applications. Precision ground bar and tight-tolerance products are especially useful for customers who require improved surface finish, dimensional consistency, and reduced secondary machining.

In many engineering applications, 17-4 PH stainless steel can maintain useful mechanical properties at moderately elevated temperatures, making it a practical choice for components exposed to mechanical load, corrosion risk, and long-term service demands.

Your Trusted Supplier for 17‑4 PH Stainless Steel

Sunxin is a professional manufacturer and global supplier of high-performance metal materials, offering 17-4 PH Stainless Steel in multiple product forms, including bars, rods, plates, sheets, tubes, pipes, wires, strips, and customized precision-processed materials. We supply 17-4 PH stainless steel under commonly recognized designations such as UNS S17400, AISI 630, Type 630, 1.4542, X5CrNiCuNb16-4, and SUS630.

With experience in materials engineering and international trade, Sunxin supports customers in medical, aerospace, oil and gas, precision machinery, chemical equipment, and industrial manufacturing fields. Materials can be supplied according to relevant standards and customer requirements, including ASTM, AMS, ISO, EN, DIN, and other international specifications.

Sunxin focuses on stable quality, reliable material traceability, accurate dimensions, and flexible customization. Whether you need 17-4 PH stainless steel bar for machining, plate for structural components, tube for precision applications, or wire for specialized manufacturing, we can provide material solutions tailored to your project requirements.

Contact Sunxin today to discuss your 17-4 PH stainless steel requirements and get reliable support for your next high-strength, corrosion-resistant engineering application.

FAQs

Typical Applications

Medical

High-hardness surgical blades / Bone drills / Dental drill bits / Micro cutting tools / Wear-resistant instrument parts

Aerospace

Precision bearings / Balls / Bearing rings / Wear-resistant control mechanism parts / Instrument rotating parts

Industrial

High-hardness bearings / Ball screw balls / Valve seats / Nozzles / Cutting tools / Wear-resistant mold parts

Robotics

Precision bearings / Joint rolling elements / Gripper wear blocks / Rotating support parts / Positioning balls

Quality Services

ERP system management, full process traceability, and good batch stability.

Furnace numbering management ensures good material consistency.

Supports third-party testing and provides reports.

Chemical composition analysis (spectrometer analysis/oxygen, nitrogen, and hydrogen analyzer)

Mechanical properties (electronic tensile testing machine/Rockwell & Vickers hardness tester/impact testing machine)

Flaw detection (UT flaw detection)

Tissue examination (metallurgical microscope/electron microscope)

Heat treatment verification

Manufacturing services

Sheets/Pipes/Bars/Wires

Tolerances customized (H6-H9 grade)

Sheets/Pipes/Bars/Wires

Length and width customized (0.1M-3M or slit/cut to order)

CNC Pre-Machining

chamfering/face treatment/grinding/turning/milling

Sheets/Pipes/Bars/Wires

Custom sizes available (any non-standard dimensions can be customized)

Dimensional and Precision Control

straightness/roundness/coaxiality/dimensional tolerance records

Customized Heat Treatment

providing heat treatment based on material properties to achieve the desired delivery condition

Surface Control

roughness/fine grinding/film application on substrate

Marking and Coding Services

laser marking/inkjet coding

Shipping Packaging

Custom Size/Separate Boxes/Long-Distance Transportation

Engineering and Technical Support Services

Start a Project

Support for medical industry applications

Supports OEM/OEM drawing processing

Material selection and alternative solutions

Tool Selection

Customized heat treatment solutions

Cost optimization

Industry-supporting resource consulting

Business & Supply Chain Services

Free samples, rapid verification

Comprehensive Product Range:We offer a wide range of products and can quickly provide samples that meet your requirements. Free trials are also available depending on your needs.

Supports small batch production and flexible MOQ

Our comprehensive product range is in stock, which can support small-batch sampling and increase flexibility.

24-Hour Quotation Response

An excellent sales and technical support team is available to provide you with dedicated service 24 hours a day.

Stable Supply Chain Production System

Stable raw material sources ensure batch consistency control. Safety stock is maintained, and production is managed according to ISO 13485 and ISO 9001 standards.