440 Series ( 440A, 440B, 440C ) stainless steel sheets ( plates ) for knives manufacturing

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US $1,000-10,000 / Metric Tons | 1 Metric Ton/Metric Tons 440A, 440B, 440C stainless steel sheets ( plates ) (Min. Order)
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Overview
Quick Details
Grade:
400 Series
Standard:
ASTM, AISI, DIN, EN, GB, JIS
Length:
cut to length, straightened
Thickness:
1mm ~
Width:
250mm
Place of Origin:
Jiangsu, China (Mainland)
Brand Name:
Changjiang
Model Number:
440 Series ( 440A, 440B, 440C )
Type:
Plate
Application:
knife blades, surgical instruments, mechanical parts ...
Certification:
SGS
delivery state:
soft annealed
SupplyAbility
SupplyAbility:
500 Metric Ton/Metric Tons per Month
Packaging & Delivery
Packaging Details
Seaworthy packing, Non - fumigation pallets with waterproof.
Port
Shanghai Port
Lead Time :
35 days after receipt the 30% advanced payment

440 Series ( 440A, 440B, 440C ) stainless steel sheets ( plates ) for knives manufacturing

Introduction

Grade 440C stainless steels are high carbon steels, which attain the highest hardness, wear resistance and strength of all stainless steel grades after heat treatment. These properties make this grade suitable for applications such as valve components and ball bearings. Grade 440A and 440B stainless steels, on the other hand, have similar properties - except for a slightly lower percentage of carbon in grade 440A.

All three forms of grade 440 steels are commonly used. However, grade 440C is more readily available than the other standard grades. Grade 440F, a free-machining type of grade 440 series, is also available with a high carbon content similar to that of grade 440C. Martensitic steel grades are high-hardness steels, usually fabricated using techniques that require hardening and tempering treatments.

These grades have a corrosion resistance lower than that of other austenitic grades. The applications of martensitic steels are limited by the loss of strength caused by over-tempering at high temperatures, and loss of ductility at temperatures below zero.

Key Properties

The following section discusses the properties of grade 440 products covered under ASTM A276. These values may not be similar to that of other forms such as forgings and plates.

Composition

The chemical compositions of various elements of grade 440 stainless steels are tabulated below:

Table 1. Chemical composition ranges of grade 440 stainless steels

 

Grade

C

Mn

Si

P

S

Cr

Mo

Ni

N

440A

min.

max.

0.6

0.75

-

1

-

1

-

0.04

-

0.03

16

18

-

0.75

-

-

440B

min.

max.

0.75

0.95

-

1

-

1

-

0.04

-

0.03

16

18

-

0.75

-

-

440C

min.

max.

0.95

1.20

-

1

-

1

-

0.04

-

0.03

16

18

-

0.75

-

-

Mechanical Properties

Table 2. Mechanical properties of grade 440C stainless steels

 

Tempering Temperature (°C)

Tensile Strength (MPa)

Yield Strength 0.2% Proof (MPa)

Elongation (% in 50mm)

Hardness Rockwell (HR C)

Impact Charpy V (J)

Annealed*

758

448

14

269HB max#

-

204

2030

1900

4

59

9

260

1960

1830

4

57

9

316

1860

1740

4

56

9

371

1790

1660

4

56

9

* Annealed properties are typical for Condition A of ASTM A276# Brinell hardness is ASTM A276 specified maximum for annealed 440A, B and C.

Grade Specification Comparison

Grade specifications for 440 stainless steels are given in the following table:

Table 4. Grade specifications of grade 440 stainless steels 

 

Grade

UNS No

Old British

Euronorm

Swedish SS

Japanese JIS

BS

En

No

Name

440A

S44002

 

 

-

-

 

SUS 440A

440B

S44003

 

 

1.4112

X90CrMoV18

 

SUS 440B

440C

S44004

-

-

1.4125

X105CrMo17

-

SUS 440C

Possible Alternative Grades

Suitable alternatives to grade 440 stainless steels are listed in the table below:

Table 5. Possible alternative grades to 440 stainless steels

 

Grade

Reasons for choosing 440C

440A/B

Slightly softer and more corrosion resistant grade needed

440F

High machinability required, with same hardness and hardenability as 440C

420

Lower strength and hardness needed than any of the 440 grades

416

Higher machinability required, and the much lower hardness and strength is still adequate

Corrosion Resistance

Grade 440 stainless steels exhibit excellent resistance to mild acids, alkalis, foods, fresh water and air. A smooth polished surface also helps grade 440 steels resist corrosion in tempered, passivated and hardened conditions.

Grade 440C steels exhibit corrosion resistance similar to that of grade 304 steels.

 

Heat Treatment

Annealing — Grade 440 stainless steels are full annealed at 850 to 900°C, followed by slow furnace-cooling at about 600°C and air-cooling. Sub-critical annealing is carried out at 735 to 785°C, followed by slow furnace-cooling.

Hardening — Grade 440 stainless steels are heated at 1010 to 1065°C, then quenched in air or oil. Oil quenching is usually carried out for heavy sections. Following this process, these steels are tempered at temperatures from 150 to 370°C, to achieve a high hardness and improved mechanical properties.

Tempering at temperatures between 425 and 565°C should be avoided as the corrosion and impact resistance properties of grade 440 tend to reduce in this range. Also, tempering of these grades at 590 to 675°C will result in high impact resistance and loss of hardness.

 

Applications

Grade 440 stainless steels find applications in the following:

· Chisels

· Surgical equipment

· High quality knife blades

· Valve seats

· Rolling element bearings

 

We are specialised in stainless martensitic steels, products in forms of hot- and cold-rolled sheet, plate, strip, coil and bars.

 

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