How it Works
Super Systems
Loading...
CarbCALC II
User Manual
47 pgs5.04 Mb0
Table of contents
Loading...

Super Systems CarbCALC II User Manual

CarbCalc II
Carbon Diffusion Model for
Atmosphere Furnaces
Copyright
Super Systems Inc
7205 Edington Drive
Cincinnati,OH 45249
CarbCalc III
Table of Contents
Part I
Part II
Introduction
................................................................................................................................... 31 Welcome to SuperSystems
................................................................................................................................... 42 CarbCalcII Introduction
CarbCalcII
................................................................................................................................... 71 Overview
................................................................................................................................... 82 Typical Uses
................................................................................................................................... 93 Menu and Toolbar
................................................................................................................................... 104 Displays
.......................................................................................................................................................... 10Atmosphere Display Area
.......................................................................................................................................................... 11Model Segment Display Area
.......................................................................................................................................................... 12Segment Properties Dialog
.......................................................................................................................................................... 13Temperature and Carbon Chart
.......................................................................................................................................................... 14Carbon Profile Chart
................................................................................................................................... 155 Users and Security
.......................................................................................................................................................... 15Login
.......................................................................................................................................................... 16Manage Users
................................................................................................................................... 176 Parts and Loads
.......................................................................................................................................................... 17Loads
.......................................................................................................................................................... 17Control Mode
.......................................................................................................................................................... 20Monitor Mode
.......................................................................................................................................................... 21BatchMaster Mode
................................................................................................................................... 237 Model and Furnace Settings
.......................................................................................................................................................... 23Settings Overview
.......................................................................................................................................................... 23Model Settings
.......................................................................................................................................................... 24Furnace Settings
.......................................................................................................................................................... 26Furnace RealTime Setup
................................................................................................................................... 288 Material Selection
.......................................................................................................................................................... 28Material Dtabase
.......................................................................................................................................................... 29Initial Carbon Profile
................................................................................................................................... 319 Target Profile
.......................................................................................................................................................... 31Specifying a Target Profile
.......................................................................................................................................................... 32Recommended Profile
................................................................................................................................... 3310 Carbobn Profiles
.......................................................................................................................................................... 33Carbobn Profile Dialog
................................................................................................................................... 3611 SuperCalc
.......................................................................................................................................................... 36The SuperCalc Application
................................................................................................................................... 3712 Simulation Mode
.......................................................................................................................................................... 37Typical Uses
3
7
......................................................................................................................................................... 18Entering a Load
......................................................................................................................................................... 19Load History in Control Mode
......................................................................................................................................................... 19Parts in Control Mode
.......................................................................................................................................................... 37Report
................................................................................................................................... 3913 RealTime Control Mode
.......................................................................................................................................................... 39Typical Uses
.......................................................................................................................................................... 39Report
................................................................................................................................... 4114 Replay Monitor Mode
.......................................................................................................................................................... 41Typical Uses
.......................................................................................................................................................... 43Report
IIContents
Part III
CarbCalcII Configuration
44
Index 0
II

1 Introduction

1.1 Welcome to SuperSystems

Super Systems Inc.
Super Systems Introduces
Load Tracking and RealTime Control
No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, electronic, mechanical, magnetic, optical, chemical, manual, or otherwise, without prior written permission of Super Systems Inc., 7205 Edington Dr., Cincinnati, OH 45249 USA.
CARBCALCII is a software program to be used by the Heat Treater. Super Systems Inc. is not responsible or liable for any product, process, or damage or injury incurred as a result of using CARBCALCII. Super Systems Inc. makes no representations or warranties with respect to the contents hereof and specifically disclaims any implied warranties or merchantability or fitness for any particular purpose.
IntroductionCarbCalc II3
CarbCalcII
with
COPYRIGHT
DISCLAIMER

1.2 CarbCalcII Introduction

CarbCalcII is a Carbon Diffusion Model for use with Batch Furnace Gas Carburizing.
IntroductionCarbCalc II 4
Gas Carburizing
low-carbon steel part at a temperature sufficient to render the steel austenitic, followed by quenching and tempering to form a martensitic microstructure. The resulting gradient in carbon content below the surface of the part causes a gradient in hardness, producing a strong, wear-resistant surface layer on a material, usually low-carbon steel, which is readily fabricated into parts. In gas carburizing the source of carbon is a carbon-rich furnace atmosphere produced either from gaseous hydrocarbons, for example, methane (CH4), propane (C3H3), and butane (C4H10), or from vaporized hydrocarbon liquids.
Carbon Sources
Low-carbon steel parts exposed to carbon-rich atmospheres will carburize at temperatures of 850°C (1560°F) and above. If the carbon source is so rich that the solubility limit of carbon in austenite is reached at the surface of the steel some carbides may form at the surface. At these "above saturation" atmospheres soot will deposit on surfaces within the furnace, including the parts. The goal of modern gas carburizing practice is to control the carbon content of furnace atmospheres such that: The final carbon concentration at the surface of the parts is below the solubility limit in austenite and Sooting of the furnace atmosphere is minimized. Endothermic gas (Endogas) is a blend of carbon monoxide, hydrogen, and nitrogen (with smaller amounts of carbon dioxide water vapor, and methane) produced by reacting a hydrocarbon gas such as natural, gas (primarily methane), propane or butane with air. A
is a case-hardening process in which carbon is dissolved in the surface layers of a
IntroductionCarbCalc II5
carrier gas similar in composition to Endogas may be produced from methane can be formed from a nitrogen-methanol blend.
Carburizing Process Variables
The gas carburizing process depends on the control of three principal variables:
·
Temperature
·
Time
·
Atmosphere composition. Other variables that affect the amount of carbon transferred to parts include the degree of atmosphere circulation and the alloy content of the parts.
Temperature
. The maximum rate at which carbon can be added to steel is limited by the rate of diffusion of carbon in austenite. This diffusion rate increases greatly with increasing temperature; the rate of carbon addition at 925°C (1700°F) is about 40% greater than at 870°C (1600°F). The temperature most commonly used for carburizing is 925°C (1700°F). This temperature permits a reasonably rapid carburizing rate without excessively rapid deterioration of furnace equipment. The carburizing temperature is sometimes raised to 955°C (1750°F) or 980°C (1800°F) to shorten the time of carburizing for parts requiring deep cases. Conversely, shallow case carburizing is frequently done at lower temperatures because case depth can be controlled more accurately with the slower rate of carburizing obtained at lower temperatures. For best results, the workload should be heated to the carburizing temperature in a near-neutral furnace atmosphere. In batch furnaces, parts can be heated in Endogas until they reach the furnace temperature; then carburizing can commence with the addition of the enriching gas.
Time.
The effect of time and temperature on the Carbon vs Depth profile shows that the carburizing time decreases with increasing carburizing temperature. In addition to the time at the carburizing temperature, several hours may be required to bring large work pieces or heavy loads of smaller parts to operating temperature. For a work piece quenched directly from the carburizing furnace, the cycle may be lengthened further by allowing time for the work piece to cool from the carburizing temperature to about 843°C (1550°F) prior to quenching. Similarly, additional diffusion and interchange of carbon with the atmosphere will occur during cooling prior to quenching.
Carbon Potential.
The carbon potential of the furnace atmosphere must be greater than the carbon potential at the surface of the work piece in order for carburizing to occur. It is the difference in carbon potential that provides the driving force for carbon transfer into the parts.
Carbon Diffusion.
The combined effects of time, temperature, and carbon concentration on the
diffusion of carbon in austenite can be expressed by Fick's laws of diffusion.
Alloy Effects.
The various alloying elements found in carburizing steels have an influence on the
activity of carbon dissolved in austenite.
Chromium
·
Nickel
·
tends to decrease the activity of carbon
tends to raise the activity of carbon The primary effect of alloys on the diffusion of carbon is their effect on the driving force at the surface reaction.
The CarbCalcII Model
CARBCALCII is a carbon difussion model for simulation and analysis of gas carburizing process for low-alloy steels. The interactions of the gas carburizing process cannot be modeled by simple one-dimensional analysis. In order to accurately predict how a low-alloy steel will react in a controlled atmosphere process, many factors must be taken into account, including:
·
Alloy steel composition
·
Equilibrium and non-equilibrium gas composition
·
Temperature
·
Atmosphere agitation
·
Surface radius of curvature, concave or convex
IntroductionCarbCalc II 6
·
Initial carbon profile CARBCALCII takes as many factors as possible into account for the accurate prediction of (1) transfer of carbon between gas and steel surface, and (2) diffusion of carbon within the steel.
Possible uses for CARBCALCII include:
·
Computer-aided design of heat treatment processes
·
Optimization of existing cycles
·
"What if" analysis when a change in an existing process or material is contemplated
·
Reconstruction of the effects that an out-of-control process may have had on a load
·
Education of personnel in the intricacies of atmosphere processing
·
Real-Time control with an on-line process CARBCALCII can pay for itself quickly because process development experiments can be carried out
quickly on the computer instead of weeks in a furnace. When a trial is finally made in the furnace, the results will be reasonably close to those predicted by the software.
CARBCALCII has thee main operating modes:
1. Simulation
2. RealTime Control
3. Monitor/Replay The object in all cases is to accurately predict the diffusion gradient that carbon establishes in a given material from a given set of processing parameters.
SIMULATION
allows construction of a diffusion gradient from complex a set of processing parameters. For example, in a batch integral quench furnace, one might be interested in the following sequence:
·
Come to Heat
·
Boost Carburize
·
Diffuse Carburize
·
Equalize for Quench
·
Brief Exposure to Vestibule Atmosphere
REALTIME CONTROL
- CarbCalcII is able to connect to "dumb controllers" via SuperData communications. In this mode, CarbCalcII becomes the "Recipe Programmer" and sends setpoints to the Temperature and Carbon Controllers.
MONITOR/REPLAY
running and logged in SuperData. This mode can be integrated with BatchMaster furnace control systems.
is used to view the Carbon Profile for load cycles previously run or currently

2 CarbCalcII

2.1 Overview

CarbCalcIICarbCalc II7
The Main Screen.
Menu and ToolBar:
·
Furnace Atmosphere Display:
·
material information and timers.
Recipe Segment Display:
·
Recipe Temperature and Carbon Chart:
·
displays segment markers.
Carbon Profile Chart:
·
Saturation Carbon line.
Provides access to Files, Printer and Model settings.
Displays Temperature, %Carbon and Gas values. Also displays
Displays the Recipe segments in the current model, (Max 8 segments).
Displays Initial Carbon, Carbon Diffusion profile, Target profile and
Displays theTemperature and Carbon vs Time. Also

2.2 Typical Uses

Simulation mode
In
·
Up to 8 segments may be modeled.
·
For each segment, define the Segment Name, Temperature, Carbon and End-Of-Segment (EOS) type.
·
EOS types are:
1. Timed - ends after a specified time.
2. Match Surface Carbon - ends when Surface Carbon matches the Target Surface Carbon.
3. Match Carbon at a specified depth - ends when Diffused Carbon matches Carbon at a specified depth.
4. Auto Boost - ends when the amount of excess carbon near the surface exceeds the deficient carbon at depth.
5. Auto Diffuse - ends when the deviation between the diffused profile and the target profile is minimized (curve matching).
·
Model Temperature units may be displayed in Celsius of Fahrenheit and Measurement units in inches or mm.
·
Probe Factors may use either the CO Factor or the Process Factor (typical to Marathon Instruments) .
·
The Type of Material may be selected from a Material Database.
·
The Initial Carbon Profile is based on the material selected and is assumed to be uniform.
·
The Initial Carbon Profile may be customized based on 10 points - useful for modeling "Rework" recipes.
·
The Target Profile (up to 10 points) may be specified or you can request a recommended profile based on Surface Carbon, Carbon at Effective Case Depth and Carbon at total Case Depth.
·
After starting the simulation, it may be paused at any time. You can also set it to "AutoPause" at the end of each segment.
CarbCalcIICarbCalc II 8
, CabcalcII is used to develop Batch Carburizing Segment recipes.
RealTime Control mode
In Controller and is used to Control a running Batch Furnace Carb Cycle.
·
A simple Load Entry system is used
·
The Segment display represents the Carb Cycle Recipe.
·
The Time vs Temperature and Carbon chart displays both the Setpoints and Actual values for Temperature and Carbon.
·
The Carbon Profile is based on actual data from the instruments.
·
Instrument communication data sources are easily configured from within the application and saved in a "Furnace" file.
Monitor/Replay mode
In data logged by the SuperSystems communications datalogger. This mode is useful in analyzing a comparing a cycle profile with the actual Profile from Lab results.· Display is similar to RealTime mode but the data source is from the historical logged data.
·
Model runs at high speed similar to simulation mode.
·
Model may be paused, stopped or restarted at any time.
·
Target profile may be used to compare actual Lab measured profile for comparison with the model results.
·
Analysis may be helpful in "Tuning" the recipe to achieve more precise results.
, CarbCalcII is connected to a Carbon Controller and a Temperature
, CarbCalcII is used to reproduce a cycle based on a Furnace Load and the

2.3 Menu and Toolbar

Menu Items
·
File
·
·
ToolBar Items
·
- Provides standard file open, save and close routines for CarbCalcII Model Files.
Help
- Opens Help file and About box.
CarbCalcIICarbCalc II9
New Model - Opens the default New Model
Save Model - saves the current model.· Print - prints the Carbon Profile report.
Model and Furnace Settings - Opens the
Model and Furnace settings dialog.
Carbon Profiles - Opens the Carbon Profiles
dialog.
Help - Opens this help file.
Open Model - displays the File Open
dialog for CarbCalcII Model Files
(report depends on model mode and settings ­see Reports in this help file)
Material - Opens the Material selection
dialog.
SuperCalc - Opens the SuperCalc
program.

2.4 Displays

2.4.1 Atmosphere Display Area

CarbCalcIICarbCalc II 10
Atmosphere
·
All atmosphere values are displayed. Model Inputs (yellow background) are "given" or "assumed" values. Monitored values (green background) are used only in the RealTime and Replay modes. Calculated values (blue background) are calculated based on Model Inputs and the assumption that the atmosphere is in equilibrium. In simulation mode, the inputs will always be Temperature, %Carbon, Probe Factor and CH4. In Realtime and Replay modes the model inputs are selectable. In these modes, data that is available but not selected as a model input may be monitored - in this case, a monitored value will be displayed next to the model value.
Temperature
·
%Carbon
·
PF or COF
·
O2mV
·
·
·
·
·
·
·
·
dependent on Temperature. When designing recipes, a good rule of thumb is to keep the %C setpoint below about 90% of the Saturation Carbon.
- Oxygen Probe millivolts
%CO
- %Carbon Monoxide in the furnace atmosphere
%H2
- %Hydrogen Monoxide in the furnace atmosphere
%CO2
- %Carbon Dioxide in the furnace atmosphere
%H2O
- %Water in the furnace atmosphere
%CH4 %C/CH4
Saturation Carbon
- units may be in Fahrenheit or Celsius.
- Carbon Potential (based on water-gas equations)
- Process Factor or CO Factor (depends on type of controller)
- %Hydrocarbon in the furnace atmosphere
- Efective%Carbon with CH4 taken into consideration
- the level at witch free carbon (soot) precipitates in the atmosphere. Primarily
Dewpoint
·
Material
·
material toolbar icon.
Timers
·
Model Run Controls
·
- displays the calculated Dewpoint for the given atmosphere.
- displays the material selected, may be changed by opening the material dialog with the
-Displays the Total elapsed time and segment elapsed time in minutes.
- Used to start, stop, pause and reset the simulation.

2.4.2 Model Segment Display Area

CarbCalcIICarbCalc II11
Model Recipe
A
Segment
·
paused or stopped, you may click on the segment name to open the segment properties dialog and edit the segment.
Temp
·
·
·
·
·
·
·
·
- The temperature for the segment. You may edit the temperature for segments that have not
yet executed.
%Carb
executed.
EOS Type
available:
RunTime Pause Checkbox
end of each segment.
Total Timer
Note:
It is not normally not displayed during Monitor and Replay modes.
- The %Carbon for the segment. You may edit the %Carbon for segments that have not yet
Timed Soak
1.
Timed Ramp
2.
Surface
3.
Depth
4.
AutoBoost
5. "Excess" carbon is the carbon above the "target" profile and "deficient" carbon is carbon below the target profile.
AutoDiffuse
6.
The Model Segment Display Area is always used in Simulation and Realtime Control Modes.
may have up to 8 Segments.
- the name given to the segment (defaults to Seg1, Seg2, etc). When the simulation is
- The End-Of-Segment type determines how the segment terminates. There are 6 types
- ends after a given time is reached.
- ramps temperature ends after a given time is reached.
- ends when the Carbon profile "matches" a specified Surface Carbon.
- ends when the Carbon profile "matches" a specified carbon at a specified depth.
- ends when the "excess" carbon is sufficient to satisfy the "deficient" carbon.
- ends when the Carbon Profile matches the Target Profile ("best fit") .
- displays the segment time in days, hours and minutes (D:HH:MM).
- (simulation and replay only) check this box to make the simulation pause at the
- displays the total time in days, hours and minutes (D:HH:MM).

2.4.3 Segment Properties Dialog

CarbCalcIICarbCalc II 12
Segment Name
·
Temperature
·
%Carbon
·
Probe Factor
·
to the Suggested PF and may be edited.
Residual CH4
·
Saturation Carbon
·
this amount.
Suggested Probe Factor
·
selected.
End of Segment Method
·
below.
- Enter or Edit the Segment Name.
- Enter or Edit the Segment Temperature
- Enter or Edit the Segment %Carbon. (PF or COF) - Enter or Edit the Probe Factor. Note: for new segments this will default
- Enter or Edit the CH4 (normally 0.0 to 5.0 depending on your furnace).
- displays saturation carbon level, %Carbon should be set to a value less than (PF or COF) - Theoretical value of the Probe Factor based on Material
- select the End of Segment type and supply required data as indicated
CarbCalcIICarbCalc II13
Delete Button
·
Insert Button
·
OK Button
·
- clicking on this button will delete this segment from the model.
- clicking this button inserts the segment as a new segment.
- exits the dialog and saves changes to the segment.

2.4.4 Temperature and Carbon Chart

Simulation mode
In executed.
RealTime
In process variables and setpoints are displayed and times are displayed as actual clock times rather than elapsed times.
and
, the Temperature and Carbon Chart displays a profile of the recipe as it is
Replay modes

2.4.5 Carbon Profile Chart

CarbCalcIICarbCalc II 14
, the Actual monitored values of the Temperature and Carbon
The Carbon Profile Chart displays %Carbon (Y axis) vs Depth (X axis).
Title
·
In RealTime and Replay Modes, displays Load Name and Model Name.
·
·
·
·
·
·
·
·
·
·
·
·
·
- In Simulation mode, displays "Model Name - Segment Name"
Y Axis X Axis Cursor Position Target Profile Lab/Other Profile Mouse Mode Restore Button Message box Carbon Profile Initial Carbon Profile Target Profile Lab/Other Profile Saturation Carbon
- %Carbon
- Depth (in inches or mm depending on model settings)
- displays the %Carbon at Depth corresponding to the cursor crosshair position.
- check to display the target profile.
- check to display the Lab or other imported profile.
- places mouse in either cursor or zoom mode (default is cursor).
- used to restore the chart after using the zoom mode.
- message display.
- primary display (filled Blue) Carbon vs Depth
- Uniform or Custom Initial Carbon Profile (Lined Cyan)
- Maroon line indicating the "spec" or Target Profile
- Green line indicating the imported Lab or other imported Profile.
- Red Line indicating the "saturation" carbon for the given furnace temperature.
Loading...
+ 32 hidden pages
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use