UNS?編碼

·?S44004

?

Carbon?碳

0.95 to 1.2

%

Manganese (Max)錳（不超過）

1.0

%

Phosphorus (Max)磷（不超過）

0.0400

%

Sulfur (Max)硫（不超過）

0.0300

%

Silicon (Max)硅（不超過）

1.0

%

Chromium?鉻

16.0 to 18.0

%

Molybdenum (Max)鉬（不超過）

0.75

%

Iron?鐵

Balance余量

?

Description/描述

?Stainless Type 440C is a high-carbon chromium steel designed to provide stainless properties with maximum hardness. It has been used primarily as a bearing steel, and is used in the hardened plus tempered condition. When heat-treated, Type 440C attains the highest hardness of any stainless steel (about Rockwell C 60). 440C含碳量高，具有不銹性能和最高的硬度。首選用途是軸承制造，是硬化加上回火狀態。當熱處理后，440C具有所有不銹鋼中最高的硬度（約HRC60）

Applications/用途

This stainless steel principally has been used in bearing assemblies, including bearing balls and races. In addition, it should be considered for cutlery, needle valves, ball check valves, valve seats, pump parts, ball studs, bushings, and wear-resistant textile components.?首選應用是軸承結構，包括滾珠和軸套。還有，它也能用來做刀具、針形閥、球型止回閥、閥門基座、泵零件、球頭螺栓、軸套、抗磨損紡織機械。

Elevated Temperature Use/高溫下的使用

?Stainless Type 440C is not usually recommended for elevated temperature applications since corrosion resistance is reduced when used in the annealed condition or hardened and tempered above about 800oF (427oC).?通常不推薦440C用于高溫環境，因為在退火或在約800oF (427oC)以上做硬化和回火狀態下，它的抗腐蝕性能下降。

?

Important Note:?The following 5-level rating scale is intended for comparative purposes only. Corrosion testing is recommended; factors which affect corrosion resistance include temperature, concentration, pH, impurities, aeration, velocity, crevices, deposits, metallurgical condition, stress, surface finish and dissimilar metal contact.?重要提示：以下5種酸性環境只用于比較，需做腐蝕測試；影響抗腐蝕性能的因素有溫度、濃度、酸堿度、雜質、通風、速率、裂縫、沉淀物、冶煉狀態、應力、表面處理和不同金屬的接觸等等。

Nitric Acid?硝酸

Moderate?中等

Sulfuric Acid?硫酸

Restricted限制

Phosphoric Acid?磷酸

Restricted?限制

Acetic Acid?醋酸

Restricted限制

Sodium Hydroxide?氫氧化鈉

Moderate?中等

Salt Spray (NaCl)

氯化鈉

?

Restricted限制

?

Humidity?濕度

Good?優秀

?

Specific Gravity重力

?????????

7.62

?

Density密度

?????????

7612

kg/m3

Mean Specific Heat平均

????????0.00 °C, 100 °C

0.4602

kJ/kg/K

Mean Coefficient of Thermal Expansion平均熱膨脹系數

????????0.0000 °C, 100.0 °C

10.1

x 10^-6?cm/cm/°C

Thermal Conductivity導熱性能

????????100 °C

24.21

W/m/K

Modulus of Elasticity (E)彈性系數

?????????

200

x 10³?MPa

Electrical Resistivity電阻

????????21.1 °C

600.0

micro-ohm-mm

Annealing/退火

For maximum softness, this steel should be heated uniformly to 1550/1600oF (843/871oC). Soak and cool very slowly in the furnace. Brinell hardness approximately 223. Intermediate or process annealing treatment-heat uniformly to 1350/1400oF (732/760oC). Air cool. Brinell hardness about 255.?要達到最軟態，此合金須均勻加熱至1550/1600oF (843/871oC)，均熱，然后緩慢爐冷，布氏硬度大約223。中間或工序間退火處理－均勻加熱至1350/1400oF (732/760oC)，空冷，布氏硬度大約是255。

Hardening/硬化

Heat to 1850/1950oF (1010/1066oC); soak; quench in warm oil or cool in air. Do not overheat. When overheated, full hardness cannot be obtained. See comments under corrosion resistance.加熱至1850/1950oF (1010/1066oC)，均熱，溫油中淬火或空冷。不能過燒。過燒就不能得到最大硬度。參見“抗腐蝕”下的評述。

?

Tempering/回火

Hardness of approximately Rockwell C 60 will be obtained. To remove peak stresses and yet retain maximum hardness, temper at least one hour at 300/350oF (149/177oC).?能達到大約洛氏硬度HRC60。為了去除峰值應力和保持最大硬度，需在300/350oF (149/177oC)溫度下回火至少一小時。

Hot Working/熱作

This steel should be handled like high-speed tool steel. Preheat to 1400/1500oF (760/816oC), then heat slowly and uniformly to 1900/2100oF (1038/1149oC). Do not forge below 1700oF (927oC), and reheat as often as necessary. Cool in a furnace if possible or in warm dry lime or ashes. Anneal after forging; cool to room temperature before annealing.

此合金須被當作高速工具鋼來處理。預熱至1400/1500oF (760/816oC)，然后緩慢并均勻加熱至1900/2100oF (1038/1149oC)。不能在1700oF (927oC)以下鍛造，盡量減少重復加熱次數。如果可能要爐冷或在溫熱干燥石灰或粉塵中冷卻。鍛造后的退火：退火前需冷卻至室溫。

Cold Working/冷作

If annealed for maximum softness, this steel can be moderately cold formed or headed.

如退火得到最軟態，此合金能被適當的冷塑或冷鐓。

Machinability切削性

For most machining operations, this steel cuts best when in the dead soft annealed condition. Because of its high carbon content it machines somewhat like high-speed steel. Because chips are tough and stringy, chip curlers and breakers are important.?為了方便切削加工，此合金在軟態退火時最易切割。因其含碳量高，切削起來與高速鋼有些相似。因碎屑堅硬而連續，配套的卷屑機和斷裂機就很重要。
The following are typical feeds and speeds for? Stainless Type 440C.?下列是此合金典型的送料和加工速度表。

Additional Machinability Notes/切削性能附件說明

When using carbide tools, surface speed feet/minute (SFPM) can be increased between 2 and 3 times over the high speed suggestions. Feeds can be increased between 50 and 100%.?當使用碳素工具時，表面速度（表面速度/秒）能增加至上表中高速部分（HIGH SPEED）的2－3倍。送料速度能提高50％－100％。
Figures used for all metal removal operations covered are average. On certain work, the nature of the part may require adjustment of speeds and feeds. Each job has to be developed for best production results with optimum tool life. Speeds or feeds should be increased or decreased in small steps.?上表數據均是標準值，具體的加工中可能需要調整速度和送料。每項工作都以最好的加工和保護刀具的使用為目標，速度和送料都可能有少許調整。

Grinding and Polishing/拋光和打磨

In cutlery applications, grinding and polishing are very important.? Stainless Steel Type 440C works well in these operations but considerable care must be used not to overheat since both the hardness and corrosion resistance may be lowered.?生產刀具時，拋光和打磨就非常重要。此合金都能很好的接受這些加工。但是請謹慎注意，不能過燒，因為過燒會使硬度和抗腐蝕性能下降。

Weldability/焊接

Because of its high-hardness capability, this steel is seldom welded. However, if welding is necessary, the parts should be preheated and maintained at about 500oF (260oC), welded, and then immediately given a 6-8 hour anneal at 1350/1400oF (732/760oC) with a slow furnace cool. The parts should not be allowed to cool below 500oF (260°C) between welding and annealing. High welding heat inputs should be used. To obtain mechanical properties in the weld similar to those in the base metal, welding consumables of like composition should be considered. Otherwise, AWS E/ER309 might also be considered.?因其具高硬度能力，此合金很少被焊接。然而，如果有必要，部件需預熱并保持在500oF (260oC)左右，焊接，然后立即在1350/1400oF (732/760oC)下進行6－8小時的退火并緩慢爐冷。部件在焊接和退火過程中不能冷卻低于500oF (260°C)。焊接時需保持高溫。為了使合金的機械性能在焊接后與焊接前的相似，應該考慮使用與焊接消耗類似的焊劑。否則就應該考慮AWS E/ER309。

Note: While this material meets the following specifications, it may be capable of meeting or being manufactured to meet other general and customer-specific specifications.?本材料除滿足下列標準外，還可以按照其他通用和客戶指定的標準生產。

·? AMS 5618

·? AMS 5630

·? AMS 5880

·? ASTM A276

·? ASTM A314

·? ASTM A473

·? ASTM A493

·? ASTM A580

·? ASTM A756

·? QQ-S-763

·? Wire

·? Wire-Rod

·? Bar-Rounds

·? Billet