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United Tru Blue II

Stainless Steel - Grade 416 (UNS S41600)

Chemical Formula

Fe, <0.15% C, 12.0-14.0% Cr, <1.25% Mn, <1.0% Si, <0.06% P, >0.15% S

Topics Covered

Background

Key Properties

Composition

Mechanical Properties

Physical Properties

Grade Specification Comparison

Possible Alternative Grades

Corrosion Resistance

Heat Resistance

Heat Treatment

Welding

Machining

Applications

Background

Grade 416 has the highest machinability of any stainless steel, at about 85% of that of a free-machining carbon steel. As for most other free-machining stainless steels the improvement in machinability is achieved by addition of sulphur which forms manganese sulphide inclusions; this sulphur addition also lowers the corrosion resistance, weldability and formability to below that of its non-free machining equivalent Grade 410.

Grade 416 is sometimes used in the unhardened or hardened and highly tempered condition because of its low cost and ready machinability.

Martensitic stainless steels are optimised for high hardness, and other properties are to some degree compromised. Fabrication must be by methods that allow for poor weldability and usually also allow for a final harden and temper heat treatment. Corrosion resistance is lower than the common austenitic grades, and their useful operating temperature range is limited by their loss of ductility at sub-zero temperatures and loss of strength by over-tempering at elevated temperatures.

Key Properties

These properties are specified for bar product in ASTM A582. Similar but not necessarily identical properties are specified for other products such as wire and forgings in their respective specifications.

Composition

Typical compositional ranges for grade 416 stainless steels are given in table 1.

Table 1. Composition ranges for 416 grade stainless steel

Grade

C

Mn

Si

P

S

Cr

Mo

Ni

N

416

min.

max.

-

0.15

-

1.25

-

1.00

-

0.060

0.15

-

12.0

14.0

-

-

-

Mechanical Properties

Typical mechanical properties for grade 416 stainless steels are given in table 2.

Table 2. Mechanical properties of 416 grade stainless steel

Tempering Temperature (°C)

Tensile Strength (MPa)

Yield Strength
0.2% Proof (MPa)

Elongation
(% in 50mm)

Hardness Brinell
(HB)

Impact Charpy V (J)

Annealed *

517

276

30

262

-

Condition T **

758

586

18

248-302

-

204

1340

1050

11

388

20

316

1350

1060

12

388

22

427

1405

1110

11

401

#

538

1000

795

13

321

#

593

840

705

19

248

27

650

750

575

20

223

38

* Annealed properties are typical for Condition A of ASTM A582.
** Hardened and tempered Condition T of ASTM A582 - Brinell Hardness is specified range, other properties are typical only.
# Due to associated low impact resistance this steel should not be tempered in the range 400-580°C

Physical Properties

Typical physical properties for annealed grade 416 stainless steels are given in table 3.

Table 3. Physical properties of 416 grade stainless steel in the annealed condition

Grade

Density (kg/m3)

Elastic Modulus (GPa)

Mean Coefficient of Thermal Expansion
(
μm/m/°C)

Thermal Conductivity
(W/m.K)

Specific Heat 0-100°C
(J/kg.K)

Electrical Resistivity (nΩ.m)

0-100°C

0-315°C

0-538°C

at 100°C

at 500°C

410

7750

200

9.9

11.0

11.6

24.9

28.7

460

570

Grade Specification Comparison

Approximate grade comparisons for 416 stainless steels are given in table 4.

Table 4. Grade specifications for 416 grade stainless steel

Grade

UNS No

Old British

Euronorm

Swedish SS

Japanese JIS

BS

En

No

Name

416

S41600

416S21

56AM

1.4005

X12CrS13

2380

SUS 416

These comparisons are approximate only. The list is intended as a comparison of functionally similar materials not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted.

Possible Alternative Grades

Possible alternative grades to grade 416 stainless steels are given in table 5.

Table 5. Possible alternative grades to 416 grade stainless steel

Grade

Why it might be chosen instead of 416

410

The high machinability of 416 can be sacrificed to gain better corrosion resistance and formability.

303

A slight drop in machinability to gain better availability. Grade 303 is non-hardenable.

182

A free-machining ferritic grade with better "soft magnetic" performance for solenoid shafts. Grade 182 is non-hardenable.

Corrosion Resistance

Useful resistance to dry atmospheres, fresh water and mild alkalies and acids, but less resistant than the equivalent non-free-machining grades. Less corrosion resistant than the austenitic grades and also less than 17% chromium ferritic alloys such as Grade 430. High sulphur content free machining grades such as 416 are totally unsuitable for marine or other chloride exposure.

Maximum corrosion resistance is achieved in the hardened condition, with a smooth surface finish.

Heat Resistance

Fair resistance to scaling in intermittent service up to 760°C and up to 675°C in continuous service. Not recommended for use in temperatures above the relevant tempering temperature, if maintenance of mechanical properties is important.

Heat Treatment

Full Annealing - Heat to 815-900°C for ½ hour per 25mm of thickness. Cool at 30°C per hour maximum to 600°C and air cool.

Sub-Critical Annealing - Heat to 650-760°C and air cool.

Hardening - Hardened by heating to 925-1010°C, quenching in oil, and tempering to suit the mechanical requirements. See accompanying table.

Note: The tempering range 400-580°C should be avoided, due to poor ductility.

Welding

Grade 416 has poor weldability. If welding is necessary use Grade 410 low hydrogen electrodes. Pre-heat to 200-300°C. Follow immediately with annealing or re-hardening, or a stress relief at 650-675°C.

A better option if the weld is not required to be hard is to use a Grade 309 austenitic stainless steel filler rod

Machining

Grade 416 offers exceptionally good machinability, the highest of any of the commonly available stainless steels. Best machinability is in the sub-critical annealed condition.

Applications

Typical applications include:

         Valve Parts

         Pump Shafts

         Automatic Screw Machined Parts

         Motor Shafts

         Washing Machine Components

         Bolts and Nuts

         Studs

         Gears

 

Source: Atlas Steels Australia

 

For more information on this source please visit Atlas Steels Australia

 

Date Added: Oct 23, 2001 | Updated: Jul 12, 2013
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