CHT 100 Steel: Properties and Key Applications

CHT 100 Steel is a high-performance steel grade classified as a medium-carbon alloy steel. It is primarily composed of iron, carbon, and various alloying elements that enhance its mechanical properties and overall performance. The key alloying elements in CHT 100 include manganese, chromium, and molybdenum, each contributing to the steel's strength, hardness, and resistance to wear and deformation.

Comprehensive Overview

The CHT 100 steel grade is recognized for its excellent combination of strength, toughness, and wear resistance, making it suitable for a variety of engineering applications. Its medium carbon content allows for good hardenability, which is essential for achieving desired mechanical properties through heat treatment processes. The presence of manganese improves hardenability and tensile strength, while chromium enhances corrosion resistance and toughness. Molybdenum contributes to the steel's strength at elevated temperatures and improves its hardenability.

Advantages:
- High Strength and Toughness: CHT 100 exhibits superior mechanical properties, making it ideal for demanding applications.
- Wear Resistance: The alloying elements provide excellent wear resistance, suitable for components subjected to friction and abrasion.
- Versatile Applications: Its properties allow for use in various sectors, including automotive, construction, and manufacturing.

Limitations:
- Weldability Challenges: The medium carbon content can make welding more complex, requiring careful consideration of filler materials and techniques.
- Cost Considerations: Compared to lower carbon steels, CHT 100 may be more expensive due to its alloying elements and processing requirements.

Historically, CHT 100 has gained traction in industries where high-performance materials are critical, establishing itself as a reliable choice for components that require a balance of strength and toughness.

Alternative Names, Standards, and Equivalents

Standard Organization	Designation/Grade	Country/Region of Origin	Notes/Remarks
UNS	G10400	USA	Closest equivalent to AISI 1045
AISI/SAE	1045	USA	Minor compositional differences to be aware of
ASTM	A829	USA	Standard specification for alloy steel
EN	1.0503	Europe	Equivalent to CHT 100 with slight variations
JIS	S45C	Japan	Similar properties, but different heat treatment recommendations

The table above highlights various standards and equivalents for CHT 100 steel. Notably, while grades like AISI 1045 and JIS S45C share similar mechanical properties, they may differ in specific alloying elements or heat treatment processes, which can affect performance in particular applications.

Key Properties

Chemical Composition

Element (Symbol and Name)	Percentage Range (%)
C (Carbon)	0.40 - 0.50
Mn (Manganese)	0.60 - 0.90
Cr (Chromium)	0.15 - 0.30
Mo (Molybdenum)	0.10 - 0.20
Si (Silicon)	0.15 - 0.40
P (Phosphorus)	≤ 0.035
S (Sulfur)	≤ 0.035

The primary alloying elements in CHT 100 steel play crucial roles in defining its properties. Carbon is essential for achieving hardness and strength, while manganese enhances hardenability and tensile strength. Chromium improves corrosion resistance and toughness, and molybdenum increases strength at elevated temperatures, making the steel suitable for high-stress applications.

Mechanical Properties

Property	Condition/Temper	Test Temperature	Typical Value/Range (Metric)	Typical Value/Range (Imperial)	Reference Standard for Test Method
Tensile Strength	Quenched & Tempered	Room Temp	850 - 1000 MPa	123 - 145 ksi	ASTM E8
Yield Strength (0.2% offset)	Quenched & Tempered	Room Temp	600 - 800 MPa	87 - 116 ksi	ASTM E8
Elongation	Quenched & Tempered	Room Temp	15 - 20%	15 - 20%	ASTM E8
Hardness (Rockwell C)	Quenched & Tempered	Room Temp	30 - 40 HRC	30 - 40 HRC	ASTM E18
Impact Strength (Charpy)	Quenched & Tempered	-20°C (-4°F)	30 - 50 J	22 - 37 ft-lbf	ASTM E23

The mechanical properties of CHT 100 steel make it particularly suitable for applications requiring high strength and toughness. Its tensile and yield strengths indicate its ability to withstand significant loads, while the elongation percentage reflects its ductility, allowing for deformation without fracture. The hardness values suggest that it can resist wear and abrasion effectively, making it ideal for components subjected to high-stress conditions.

Physical Properties

Property	Condition/Temperature	Value (Metric)	Value (Imperial)
Density	-	7.85 g/cm³	0.284 lb/in³
Melting Point	-	1425 - 1540 °C	2600 - 2800 °F
Thermal Conductivity	20°C	45 W/m·K	31 BTU·in/h·ft²·°F
Specific Heat Capacity	20°C	0.46 kJ/kg·K	0.11 BTU/lb·°F
Electrical Resistivity	20°C	0.0000017 Ω·m	0.0000017 Ω·in
Coefficient of Thermal Expansion	20°C	11.5 x 10⁻⁶/K	6.4 x 10⁻⁶/°F

The physical properties of CHT 100 steel are significant for its applications. The density indicates a robust material, while the melting point suggests good thermal stability. Thermal conductivity is essential for applications involving heat transfer, and the specific heat capacity reflects its ability to absorb heat. The electrical resistivity is relatively low, making it suitable for applications where electrical conductivity is a factor.

Corrosion Resistance

Corrosive Agent	Concentration (%)	Temperature (°C)	Resistance Rating	Notes
Chlorides	3-5	25	Fair	Risk of pitting
Sulfuric Acid	10	60	Poor	Not recommended
Sodium Hydroxide	5	25	Good	Moderate resistance
Atmospheric	-	-	Good	Susceptible to rust

CHT 100 steel exhibits varying degrees of corrosion resistance depending on the environment. In chloride-rich environments, it shows fair resistance, with a risk of pitting corrosion. In contrast, exposure to sulfuric acid is not recommended due to poor resistance, while it performs moderately well in alkaline conditions. Compared to stainless steels, CHT 100's corrosion resistance is limited, making it less suitable for highly corrosive environments.

Heat Resistance

Property/Limit	Temperature (°C)	Temperature (°F)	Remarks
Max Continuous Service Temp	400	752	Suitable for prolonged exposure
Max Intermittent Service Temp	500	932	Short-term exposure only
Scaling Temperature	600	1112	Risk of oxidation beyond this temp
Creep Strength considerations	400	752	Begins to degrade at elevated temps

At elevated temperatures, CHT 100 steel maintains its strength and toughness up to approximately 400°C (752°F) for continuous service. Beyond this temperature, the risk of oxidation and scaling increases, which can compromise the material's integrity. Creep strength becomes a concern at temperatures above 400°C, necessitating careful consideration in high-temperature applications.

Fabrication Properties

Weldability

Welding Process	Recommended Filler Metal (AWS Classification)	Typical Shielding Gas/Flux	Notes
MIG	ER70S-6	Argon + CO2	Preheat recommended
TIG	ER70S-2	Argon	Post-weld heat treatment may be needed
Stick	E7018	-	Requires careful control to avoid cracking

CHT 100 steel can be welded using various methods, but it requires careful attention to preheat and post-weld heat treatment to avoid cracking due to its medium carbon content. The selection of filler metals is crucial for maintaining the integrity of the weld. MIG and TIG processes are commonly used, with specific filler metals recommended to ensure compatibility and performance.

Machinability

Machining Parameter	CHT 100	AISI 1212	Notes/Tips
Relative Machinability Index	60	100	CHT 100 is less machinable than AISI 1212
Typical Cutting Speed	30 m/min	50 m/min	Adjust tooling for optimal performance

CHT 100 steel has a machinability index of around 60, indicating it is less machinable than some other grades like AISI 1212. Optimal cutting speeds should be adjusted based on tooling and machining conditions to achieve the best results.

Formability

CHT 100 exhibits moderate formability, making it suitable for cold and hot forming processes. However, care must be taken to avoid excessive work hardening, which can lead to cracking. The recommended bend radii should be adhered to, especially in cold forming applications, to maintain material integrity.

Heat Treatment

Treatment Process	Temperature Range (°C)	Typical Soaking Time	Cooling Method	Primary Purpose / Expected Result
Annealing	600 - 700	1 - 2 hours	Air	Softening, improving ductility
Quenching	800 - 900	30 minutes	Oil or Water	Hardening, increasing strength
Tempering	400 - 600	1 hour	Air	Reducing brittleness, improving toughness

Heat treatment processes such as annealing, quenching, and tempering are essential for optimizing the properties of CHT 100 steel. Annealing softens the material, while quenching increases hardness. Tempering is crucial for reducing brittleness and enhancing toughness, allowing the steel to perform effectively in various applications.

Typical Applications and End Uses

Industry/Sector	Specific Application Example	Key Steel Properties Utilized in this Application	Reason for Selection
Automotive	Gears and shafts	High strength, wear resistance	Essential for durability and performance
Construction	Structural components	Toughness, weldability	Critical for load-bearing applications
Manufacturing	Tooling and dies	Hardness, wear resistance	Necessary for longevity and precision

In the automotive sector, CHT 100 is often used for gears and shafts due to its high strength and wear resistance. In construction, its toughness and weldability make it suitable for structural components. Additionally, in manufacturing, tooling and dies benefit from the hardness and wear resistance of this steel grade, ensuring longevity and precision in production processes.

Important Considerations, Selection Criteria, and Further Insights

Feature/Property	CHT 100	AISI 1045	S45C	Brief Pro/Con or Trade-off Note
Key Mechanical Property	High Strength	Moderate Strength	Moderate Strength	CHT 100 offers superior strength
Key Corrosion Aspect	Fair	Poor	Fair	CHT 100 is better in some environments
Weldability	Moderate	Good	Good	CHT 100 requires careful welding
Machinability	Moderate	Good	Good	CHT 100 is less machinable
Formability	Moderate	Good	Good	CHT 100 has limitations in forming
Approx. Relative Cost	Higher	Moderate	Lower	CHT 100 may be more expensive
Typical Availability	Moderate	High	High	CHT 100 may be less readily available

When selecting CHT 100 steel, considerations such as cost, availability, and specific mechanical properties are crucial. While it offers superior strength and wear resistance, its higher cost and moderate machinability may influence decisions in favor of alternative grades like AISI 1045 or S45C, depending on the application requirements. Understanding the trade-offs between these grades is essential for optimizing performance and cost-effectiveness in engineering applications.