gas nitriding zeroflow(r) webinar, oct. 18, 2016

The world's leading producer of heat treatment equipment

Best Nitriding Technology: ZeroFlow®

October 18, 2016


Faces for Radio

2

Director - Thermal ProductsMark Hemsathe: [email protected]: 419-356-3500

Director – Aftermarket & MarketingDoug Glenne: [email protected]: 724-923-8089


Overview

3

/ Who is SECO/WARWICK?

/ Technology and R & D Capabilities

/ Gas Nitriding – ZeroFlow® Technology/ What is Nitriding/ Gas Savings with ZeroFlow/ Success Stories/ - FNC Truck Gears/ - Nitriding Extrusion Dies


Poll Question #1

4

/ What type of Nitriding do you currently do?

The world's leading producer of heat treatment equipment 5

vacuum furnaces

thermal furnaces

melting furnaces CAB aluminum

process

SECO/WARWICK - Broad Range of Thermal Processing Solutions


Ukiah, CA Meadville, PA

Europe

IndiaChina

Global Presence


Technology and Research & Development


R&D

8

/ Industrial-sized Furnaces and Metallographic Laboratory

/ Demonstrate equipment performance and technology with customer parts

/ Cooperation with Industry & Universities

/ Domestic & International R&D Projects

/ Technology Development/ Single Piece Flow LPC/HPGQ/ Gas Heated Vacuum/ Plasma Activation in Gas Nitriding


R&D - Furnaces

9


Plasma Activation Gas Nitrider


ZeroFlow® Gas Nitriding


Pusher Walking Beam/Hearth Car Bottom Box

Rotary Retort Rotary Hearth Bell Tip-Up

Roller Hearth Mesh Belt Batch Retort Pit

Continuous Production Batch Production

Most Common Equipment Types

12


ZeroFlow® Nitriding - Retort

13

/ Sealed Retort Based Process

/ Available in Vertical or Horizontal Configuration

/ Available in Electric or Gas Heated Option

/ Available in Multiple Sizes, up to 13,000 lbs Gross Load

/ Capable of Multiple Processes/ Gas Nitriding/ Ferritic Nitrocarburizing/ Post-Oxidation

/ Fulfill AMS2750D, AMS2759/10/12

/ ZeroFlow Process reduces consumption of NH3

Verti

cal F

urna

ces

Horiz

onta

l Fur

nace

s


What is gas nitriding?

Gas nitriding is a process which consists of saturating the steel parts surface with available nitrogen (free nitrogen atoms), while the parts are at nitriding temperature. The process is time and atmosphere dependent:

2NH3 3H2 + 2N

Fe

in order to achieve:

• high surface hardness• good fatigue resistance• galling, adhesion and cavitation wear resistance• improved corrosion resistance in iron.

SECO/WARWICK©


What is FNC?

Similar to Gas Nitriding, but free Carbon is added to assist with adding both carbon to the surface and Nitrogen in the metal :

Carbon can be added in the form of CO, CO2 or other gases.

2CO [C] + CO2

• FNC is a faster way to add surface hardness to low carbon steels• Improved corrosion resistance in iron, especially after high

temperature oxidation over compound layer.


The structure of nitrided layer

e – Fe2-3N zone

g’ – Fe4N zone

a – FeN zone


Two-stage nitriding (Floe process) with use of NH3+ dissNH3 mix (or N2, H2)

NH3

NH3

dissNH3

dissociator

NH3+dissNH3

furnace

A

valves

gas flowmeters

gas analyzer


Gas Consumption

18


The growth kinetics of nitrided layer is controlled by 2 parameters: T & Np

The nitrided layer – e+g’+a or g’+a or a (grinding is not required)

Time process

Nitr

idin

g pa

ram

eter

sControl gas nitriding with use of NH3 – ZeroFlow process

TT

QNH3

KN

QNH3

I stage: NH3

II stage: NH3

KN


Gas Consumption

20

/ In largest installation of ZeroFlow to date, Reduction of Ammonia 8:1

/ Replaced Pusher style furnace with 5 large Retort units

/ Ammonia use went from 160 Metric Tons to 20 Metric Tons!


Process Benefits:

• ZeroFlow is Gas Nitriding.

• ZeroFlow nitriding: Lower consumption of process gas.

• ZeroFlow nitriding: Easy control of growth Kinetics of the nitrided

layer.

Recap of ZeroFlow® Solution for Gas Nitriding


Equipment Design:

• Vacuum Purge: Lower consumption of Nitrogen gas.

• Turbo Cooler: Shorter Cycle leads to more productive unit

• Convection: Very critical in Uniform gas nitriding

• Electric or Natural Gas: Designs to heat with either.

Recap of ZeroFlow® Solution for Gas Nitriding


Comparison of NH3 consumption and N2 +H2O

emission during nitriding of crankshaft in ZeroFlow® and

Floe process

0

5

10

15

20

25

30

35

40

45

50

consumption emission

NH 3

cos

nsum

tion

and

N 2 + H

2O e

mis

sion

, m3

ZeroFlow

Floe

ZeroFlow

Floe

4340St. I: 490oC, 2h, rN=25atm-1/2

St. II: 530oC, 15h, rN =0.6atm-1/2

St. III: 530oC, 12h, rN =0.4atm-1/2


NH3 and N2 consumption as well as gas emission H2O & N2 during nitriding of crankshaft using current processes

0

10

20

30

40

50

Gas

con

sum

ptio

n an

d em

issi

on, m3

NH3 and N2 consumption H2O+N2 emission

NH3ZeroFlow

NH31-stage

NH3+NH3zdys.2-stages

NH3+N2

NH3ZeroFlow

NH31-stage

NH3+NH3zdys.2-stages

NH3+N2

40 NiCrMo 6I st.: 490oC, 2h, KN = 15II st.: 530oC, 15h, KN = 0,6III st.: 530oC, 13h, KN = 0,4

N2

NH3

NH3

NH3

NH3


Hardness distribution

0

100

200

300

400

500

600

700

800

0 0,1 0,2 0,3 0,4 0,5 0,6

Distance from the surface, [mm]

Har

dnes

s, H

V 0

,1

4340I st.: 490oC, 2h, Np =2 5

II st.; 530oC, 15 h, Np =0,6III st.: 530oC, 12 h, Np =0,4

gefHV400 = 0,4mm

gefHV600 = 0,15mm


Compound layer on 4340


Ferritic nitrocarburizing of teeth on truck engine gears – 8:1 Reduction NH3


Nitrocarburizing Requirements

• Compound zone: 10-15 µm• Effective Case Depth (DNC): minimum 0,30 mm

(core hardness + 50HV criterion)• Porosity < 40%


Root of tooth Flank of tooth


Ferritic nitrocarburizing of teeth on truck engine gears


Poll Question #2

31

/ Do you have trouble with Compound (White) Layer control?


Ferritic nitrocarburizing of teeth on truck engine gears


Aluminum extrusion dies tests:ZeroFlow® nitriding layer control tests layer phase

structure, thickness, and hardness were performed on samples from H13 in the form of slices cut from dies.

die divided into slices

dimensions of a part represented dies for extruding

hollow profiles dimensions of a part represented

dies for extruding flat profiles

track

gap


Distribution of hardness in slices of dies nitrided with the ZeroFlow® method for different

parameters of stage II of the process; (stage I parameters: T=490°C, KN=15 atm-½, t=1 h)

Varying the Kn & Time, and Resultant Layer Profile


a) “hollow” b) “hollow”

c) „gap” d) „gap”

Structure of the calibrating belt of a cutting of a die nitrided with: Stage I KN=15 atm-½; t=1 h, T=490°C, Stage II KN=0.4 atm-½; t=55 h,

T=550°C,a-b) on the side of the hollow, c-d) on the side of the gap


Aluminum Processed before Die Failure


a) “hollow” b) “hollow”

c) „gap” d)„gap”

Structure of the calibrating belt of a cutting of a die nitrided with: Stage I KN=15 atm-½; t=1 h, T=490°C, Stage II KN=1.0 atm-½; t=55 h, T=550°C,a-b) on the side of the

hollow, c-d) on the side of the gap


0

2

4

6

8

2 4 6 8 10

Time [h]

Thic

knes

s of

e+

g ' zon

e [m m

]

0

1

2

3

4

Nitr

idin

g po

tent

ial K

N

KN

e+g'

4140530oC

II stage

I stage20 l NH3/min

KN

The kinetics of growth and reduction of the e+g zone in a two-stage process – sample of the 4140 steel:1st stage: 100%NH3,2nd stage: NH3 inflow entirely closed (variant 1) or atmosphere changed to NH3+NH3diss. (variant 2)

variant 2with a flow of NH3+NH3diss.

zero flow of NH3


Absorption isotherm of nitrogen in the e-Fe2Ny phase, determined experimentally in atmospheres obtained from NH3, NH3+H2 and NH3+NH3diss.

8

8,4

8,8

9,2

9,6

10

0 4 8 12 16 20

Nitriding potential KN

Nitr

ogen

con

tent

[%N

]

e-Fe2N1-y phase500oC

equilibrium was determined in:NH3+H2 mix flowing through a quarz retort NH3+NH3diss. mix circulating in steel retort (without its flow through the retort)


Equipment Designs for Gas Nitriding


HRN horizontal nitriding furnace

Exhaust hatchHeating

elements

Cooling air blower

Cr-Ni retort

Atmosphere mixer

Light insulation


VRN vertical nitriding furnace


?Questions?

Thank You

[email protected]

gas nitriding zeroflow(r) webinar, oct. 18, 2016

Engineering