Aço D2 vs Aço 1095: Qual é a diferença?

Aço para ferramentas D2 and 1095 carbon steel are distinct materials with different compositions, properties, and applications, making them suitable for vastly different purposes. The primary distinction lies in D2 being a high-alloy tool steel designed for wear resistance and dimensional stability. At the same time, 1095 is a high-carbon plain steel, often used for its hardness after heat treatment. We will introduce two types of steel separately and then compare them.

Introduction of D2 steel

Classification and Composition

O aço D2 é um aço com alto teor de carbono e alto teor de cromo aço para ferramentas de trabalho a frio. It is also known as an air-hardening steel. Typical composition ranges for D2 include approximately 1.40-1.60% Carbon, 11.00-13.00% Chromium, 0.70-1.20% Molybdenum, and 0.50-1.10% Vanadium.

Propriedades

1. Resistência ao desgaste: D2 steel contains a large amount of hard, chromium-rich M7C3-type carbides, which provide it with excellent vestir resistance. Higher carbon D-series steels, such as Aço ferramenta D3 or D6 (similar to D3), have even higher carbide content, providing better wear resistance than D2.
2. Dureza. Dureza do aço D2 can be achieved at 58-64 HRC after heat treatment.
3. Toughness. Compared to other tool steels, such as Aço para ferramentas A2 or S series impact-resistant steel, D2 steel exhibits lower wear resistance. However, in actual use, the wear resistance of D2 steel can also be considered good. The high volume of carbides that contribute to wear resistance can also reduce toughness.
4. Estabilidade dimensional. D2 steel has excellent dimensional stability during heat treatment. Expansion or contraction can be as low as approximately 0.0005 inches per inch. (0.0005 mm/mm) When air quenched from proper hardening temperatures.
5. Usinabilidade e retificação. D2 is difficult to machine and grind, primarily because of its high chromium content and carbon range. Its machinability rating is 45 compared to a 1% carbon steel rated at 100.
6. Soldabilidade. D2 tool steel is difficult to weld or non-weldable by conventional methods because of its high carbon content and significant amount of carbides.
7. Fracture Behavior: Under tensile loading, D2 steel typically shows almost no necking prior to fracture (around 1.3% area reduction) and exhibits a flat fracture surface. The surface fracture morphology tends to be rougher with larger microvoids compared to O1 steel.

Aço para ferramentas D2 Tratamento térmico

D2 is an air-hardening steel. A typical hardening temperature ranges from 1010 to 1095 °C (1850-2000 °F), followed by air quenching. Tempering is often performed in two or even three cycles, typically in the range of 205-540 °C (400-1000 °F), with specific recommendations around 480-515 °C (900-960 °F) to refine grain structure and improve wear resistance and stress relief. Overheating during hardening can lead to increased retained austenite, which might reduce desired hardness. For more information about this topic, please read Como tratar termicamente o aço D2 adequadamente.

Aplicativos

D2 steel is widely used for long-run stamping applications, blanking and cold-forming punches and dies, piercing punches and dies, forging operations, and trimming tools. It is also used as an insert in tougher steel casings for dies. Find more information about D2 steel applications in tool making.

Introduction of Aço 1095

Classification and Composition

1095 steel is a simple high-carbon steel. Its composition is typically 0.90-1.03% Carbon and 0.30-0.50% Manganese.

Propriedades

1. Dureza. 1095 steel is capable of achieving high hardness after quenching, for example, a Rockwell C hardness of 42 after quenching and drawing.
2. Resistência ao escoamento. The yield strength of 1095 steel varies depending on factors like bar thickness and the severity of quenching. Smaller bars and those quenched more rapidly from austenitizing temperature tend to have higher yield strength.
3. Ductility and Toughness. Ductility is influenced by hardness, generally decreasing as hardness increases. 1095 steel can achieve improved ductility at a given hardness compared to plain carbon steel, such as 1060, when alloyed.
4. Scuffing Resistance. Its resistance to scuffing is very low (<1) when compared to cast irons with various graphite structures (1.11 to >1.45).
5. Resistência à corrosão: Plain carbon steels, such as 1095, are generally more susceptible to corrosion compared to weathering steels like Cor-Ten.

Tratamento térmico

1095 steel can be oil quenched, gas quenched (forced air), or cooled in still air (normalized) from austenitizing temperatures (e.g., 900 °C/1650 °F) to achieve different hardness levels. For example, 1095 steel can be water quenched from 1000 °C (1830 °F) to form a needle-like structure. The rate of cooling for 1095 steel can be increased by a very light scale (0.08 mm/0.003 in.), but a heavy scale (0.13 mm/0.005 in.) retards it.

Aplicativos

1095 steel is a simple high-carbon steel. It is a candidate material for gears.

Direct Comparison: D2 Steel vs. 1095 Steel

Recurso	Aço para ferramentas D2	1095 Carbon Steel
Type/Class	High-carbon, high-chromium cold-work tool steel; air-hardening.	Simple high-carbon steel.
Composição	High alloy content (1.5% C, 12% Cr, 0.8% Mo, 0.9% V) for carbide formation and hardening.	High carbon (0.90-1.03% C) with low or no significant alloy additions, typically 0.30-0.50% Mn.
Primary Strength Mechanism	Relies on high volume of hard alloy carbides (M7C3) and secondary hardening from tempering.	Carbon content allows for high hardness through martensitic transformation upon quenching, but without significant secondary hardening.
Resistência ao desgaste	Excellent to very high standard for abrasion resistance. Superior to 1095 due to stable alloy carbides.	Good for basic applications after hardening, but significantly lower than D2. Wear resistance tends to increase with the amount/size of carbide particles, resulting in very low scuffing resistance.
Dureza	High (58-64 HRC).	High after quenching (e.g., 42 HRC), but can vary. Lower than D2 in high-wear applications.
Robustez	Moderate to fair.	Can achieve reasonable toughness for its class, but generally lower than alloyed steels at comparable hardness levels. Less resistance to brittle fracture compared to medium-alloy hot-work steels.
Estabilidade dimensional	Excellent, minimum distortion	Since water quenching is often used for complete quenching, its internal stability is relatively poor.
Usinabilidade	Difficult to machine and grind.	Difficult or non-weldable by conventional methods.
Soldabilidade	Difficult or nonweldable by conventional methods.	Can be welded, but requires careful handling to prevent potential hydrogen-assisted cracking.
Comportamento de fratura	Water, oil, or gas quenching from austenitizing temperatures (e.g., 900 °C/1650 °F). Tempering to achieve the desired hardness-toughness balance.	High-carbon steels typically show less ductile fracture than lower-carbon steels.
Tratamento térmico	Air hardening from 1010-1095 °C (1850-2000 °F), typically double or triple tempered between 205-540 °C (400-1000 °F).	Water, oil, or gas quenching from austenitizing temperatures (e.g., 900 °C/1650 °F). Tempering to achieve desired hardness-toughness balance.
Custo	Higher cost	Long-run dies, blanking and cold-forming punches, trimming tools, and piercing punches.
Aplicações típicas	It can achieve reasonable toughness for its class, but generally lower than alloyed steels at comparable hardness levels. Less resistance to brittle fracture compared to medium-alloy hot-work steels.	Gears, general high-hardness components, or when simple heat treatment is preferred.

Resumo

D2 steel is engineered for extreme wear resistance and dimensional stability in high-performance tooling applications, making it suitable for long production runs where the tool material contributes significantly to overall costs in large dies. 1095 steel, on the other hand, is a more economical, simpler high-carbon steel chosen for applications requiring general high hardness and strength, without the need for D2’s superior wear properties or complex alloy additions.