These factors are then totaled in the third column. For large steel assemblies in particular, PWHT can be an expensive operation, and there is thus an economic incentive to avoid PWHT, wherever possible. Every year, the individual price sheets were multiplied by an inflation factor and re-issued. Allocation of Repairs/Maintenance and Fixture/Tooling Costs. Calculation: for heat on object. Ideally for austenitization , the holding time is decided based on sample size but is there a thumb rule ?      The allocated costs (as applicable) are entered next with the allocated portion entered as “Allocated $/Year.” This number is then divided by the utilized hours/year to give the contribution of the allocated costs to the total cost. 128-130A. Â.      After the direct labor, benefits and total energy costs are calculated, they are totaled, resulting in the total variable cost. PT 470, 510, 610 & 710; Protherm 455; AE25 – 1/4DIN; Protherm 10; AE06L – 1/16DIN; ActivePLC™ / ActiveHMI™ Protherm 50; Carbonsender™ Legacy Products; Measuring Devices / Analyzers. 2.   The data can be used to calculate selling prices (per pound or each piece) when the cycle length and loading characteristic are known. If a company has a main platform for process control, it most likely has the ability to record data from sensors on equipment usage, gas usage, kilowatt consumption, water, etc. All assignable costs for a piece of equipment usually cannot be specifically assigned and tracked in an accounting system. Figure 8: Structure of calculations Upon entering the screen for the calculations, see figure 9, the user must first select the process of interest, the options being PLz help me to understand what is Grain Size and Grain Number. The endothermic gas was supplied by two 3,600-CFH, automatic dew-point controlled and air-cooled generators. Three of the batch tempering furnaces were also equipped for nitrogen tempering. The columns are titled: Quantity, the number of similar units; Use or Size, size or rating of the similar units measuring units for the component; Duty Cycle, the portion of time cycle the unit is functioning during the heat-treating cycle; Total Use, conversion of the units to the common-use category; and $/Unit of the Yearly Commodity Cost from Table 1. For the purpose of calculating the heat treatment processing cost per hour and the selling price for a piece of equipment, the costs are separated into direct costs, allocated costs, capitalized cost, and general and administrative costs. Heat treatment is the process of heating and cooling metals to change their microstructure and to bring out the physical and mechanical characteristics that make metals more desirable. But if you mean some sertain kind of heat treatment there are of course some ways to calculate the time needed. Using this schedule, allowing for holidays, the available hours of operation were 350 x 24, or 10,704 hours per year for each piece of primary equipment. / Metallurgical Engineering. heat treatment is the type, consistency and control of the furnace atmosphere. Using thumb rules as stated above is lot easier.Â. A weighted factor is assigned to each piece of equipment based on its age and the severity and frequency of repairs.      After heading the spreadsheet with the equipment name, date the sheet was prepared and any other applicable details, the actual use and cost data can be entered after all utility-use data is gathered. The two-zone batch atmosphere furnaces were kept in certification to AMS 2750 as well as two companion tempering furnaces. Heating Rate in °C/h, °F/h. The processes used were carburizing, carbonitriding, harden and temper, atmosphere annealing and carbon restoration. An advantage of the system would be that if the loading characteristics of individual parts a… For example those proposed by Anil Kumar V. Cite So, for plate 5 mm thick use 10-20 mins. Heat treatment is a process or a combination of processes to treat metallic components. The outer diameter of the steam line is 18 in. Even inside one type of operation the time required may vary significantly. For temperiing it would be 2 Hr/Inch. The costs could then be accurately assigned to the hourly cost of operation for each piece of equipment or similar groups of equipment. The basis for each allocation needs to be well thought out and make sense for the operation. This system was in turn kept cool by two evaporative cooling towers. Ghulam Ishaq Khan Institute of Engineering Sciences and Technology. The fourth column lists the certified equipment. Allocation of repairs/maintenance and fixtures/tooling costs, Fig. Overall atmosphere work accounted for about 52% of overall sales. thc = Time in hours calculated to compensate for the heating or cooling portion of the heat treatment cycle. Heat treatment is the single most important factor in determining performance of the steel. Repairs/maintenance includes the cost of outside purchases of replacement materials and services used to maintain the equipment such as fans, motors, bearings, radiant tubes, refractory, hearths or skid rails, etc. The objective was the development of a simple, cost/pricing system that would be reasonably accurate and could easily be recalculated if the yearly costs of any of the basic cost components change. In this experience, the company had pages and pages of prices by the pound for each of the many treatments that were offered.      Finally, a summary of all the selling prices for the primary equipment is shown in Table 2. Carbon Steel Typical Heat Treatment. Heat treatment is an essential process for many critical parts of an airplane, so it is understandable that there are tight regulations and audit processes set. These treatments accounted for about 13% of total sales. The average hourly cost per furnace is shown in the last column. Relation between ASTM Grain Size and Grain number? Thesis--University of Missouri--Rolla. It is then held for a time until it is quenched, causing the material to retain the properties of the solution. The figures shown are for applications where a temperature is being maintained ; this calculator does not show calculations for raising a pipe to a specific temperature. T = Holding temperature in degrees Celsius for the heat treatment. There are certain thumb rules as given by a researcher in the answer. 2. For a wall of steady thickness, the rate of heat loss is given by: Finally, a factor is determined in the fourth column, which is the weighted value for the equipment category. After 760 C for 2 hours PWHT (Post Weld Heat Treatment) of welded material, its Grain Size and Grain Number will increases or decreases as compare to Point (1) weld? Quenchant costs include the cost of additive quench materials such as water, polymers, oils, gases used for quenching, etc. 9. There was one large gas-fired, recirculating air furnace (certified) served by a manipulator for handling up to 3,000-pound loads of aluminum. First, however, the allocated costs of process control and repairs/maintenance need to be determined (as follows) for the generator operation. Shortfalls in pricing for specific equipment or processes could then be identified for possible corrective action.      Table 2 calculates some selling prices per pound based on cycle length. Cooling Rate in °C/h, °F/h. Process-control costs include the outside purchases of replacement thermocouples, protection tubes, instrumentation checks, instrument replacements, periodic furnace surveys, and thermocouple and temperature calibration checks. With the development of new alloys for coatings, it is even more important than ever to understand how something as generic as sample preparation can affect the evaluation of a coating. Although it is recognized that each heat-treating operation is unique and the prices presented in this paper may not be applicable, the technique presented can be useful in the derivation of accurate costs and prices. Each unit had program-controlled dual scanners, which were also bussed for continuous-use applications. Heat exchange by conduction can be utilized to show heat loss through a barrier. Tr will vary depending on whether F0 is being calculated or whether a pasteurisation process or other heat treatment e.g. Cite. Cost of setup or tooling : Here, use any "one time" cost that the vendor requires.      Later, as manager of a commercial heat-treating operation where errors in heat-treat pricing could affect the very success and profitability of the company, accurate pricing was an important issue. Fig.      Earlier published work[1] grouped the heat-treating costs into the same general category by process and, thus, were not assigned to specific equipment. the average hourly cost for direct labor) can easily be determined.  Room temperature is a constant. How we can decide the post heat treatment temperature range for any metal or for alloys. When questioned, those responsible for quotations and pricing were not sure how most of the prices were originally derived, but “the prices had been determined several years ago and then annually updated.”. This data can also be seen on the graph of stress over strain and tension over extension, and also in the picture of the microstructure. http://products.asminternational.org/hbk/index.jsp, Estudos de degradação e de passivação de biomateriais utilizados em cirurgia ortopédica, A electrodeposição sobre alumínio : Tratamentos prévios em solução modificada de zincato. Finally, the total hourly cost is the total of the last three figures in the right column. Visit our updated, This website requires certain cookies to work and uses other cookies to help you have the best experience. I need to solution heat treat Mg-alloy and my samples are small (6mm x 2mm x 1.5mm) so I wanna know do I have to heattreat them for 24h or for lesser time ? The other unique features added to these spreadsheets are the line for efficiency factor (profit) contribution to selling price. 1. C = Constant (Unique … The atmospheres used in the heat-treat industry have one of two common purposes: † To protect the components being pro-cessed from harmful chemical reactions Heat treatment could be said to be a method for strengthening materials but could also be used to alter some mechanical properties such as improving formability, machining, etc. 2.   Air and Natural Gas Flow Capacity Chart (SCFH), Hauck Manufacturing Co., Lebanon, PA, www.hauckburner.com. The nitrogen flows for nitrogen purging were set at each furnace to be the same as the endothermic gas flows. Heat Treatment: Tuning of material properties. 7. There were three RF (50, 60 and 150 kW) units and two 3/10 kHz (100 and 150 kW) units. The challenge for the customer is determining whether a proper heat treatment has been performed. In another example, according to a Latrobe Steel data sheet, 17-4 precipitation hardening stainless steel can typically be expected to shrink by 0.0004 to 0.0006 inch/inch (size change per unit of length) when aging from Condition A to Condition H-900 and 0.0018 to 0.0022 inch/inch when aging from Condition A to Condition H-1150. In Figure 3, each piece of primary equipment is again shown in the first column and direct annual costs are available for the groups of equipment as shown. All rights reserved. The purpose of a furnace atmosphere var-ies with the desired end result of the heat-treating process. The known costs are then allocated by the attributed percentage of components in each category. and the outer surface temperature is 280 o F. The convective heat transfer coefficient for the air is 18 Btu/hr-ft 2 - o F. Direct labor is the hourly cost of labor for those directly involved in doing the process. Allocated costs often are a series of smaller costs, more difficult to directly assign, for which average and cumulative costs can be more accurately assigned by specific equipment or similar equipment. Related. General and administrative (G&A) costs would include everything else not directly assigned, including the cost of administrative, supervisory function, all indirect personnel with related benefit costs, building cost, building maintenance and general utilities. Two concentrations of temperature-controlled polymer quench (5% and 20%) were available for use in holding tanks at each unit. For the purpose of calculating heat-treat processing cost per hour for a piece of equipment and ultimately the selling price, costs are separated into the following categories: direct costs, allocated costs, capitalized cost, and general and administrative (G&A) costs.      Figures 7 and 8 show cost sheets for two different frequency (RF and 3/10 kHz ) induction hardening machines. How to decide holding time for any heat treatment ? Visit our updated, Heat & Corrosion Resistant Materials / Composites, Commercial Heat Treat Capabilities Directory, Materials Characterization & Testing Equipment Directory, Cutting Automotive Die Costs Using Laser Heat Treating, Heat Treating: On-Site Hydrogen Generation Can Cut Atmosphere Costs, Heat Treating: Design of Quench Systems for Aluminum Heat Treating, Part II - Agitation, Heating Elements Dictate Life-Cycle Performance and Operating Costs of Electric Furnaces and Ovens, Gasbarre Thermal Processing Systems (OEM of J. L. Becker Brand Products), Materialographic Preparation of Thermal Spray Coating Samples. Chromium Nickel Steels Not Hardenable by Heat Treating .      In Figure 1, the average hourly cost of nitrogen for all atmosphere furnaces is determined by dividing the overall cost ($29,853) by the total utilized hours (30,071), which is $0.993.      Sales and utilization data were recorded for similar classes of these furnaces. Use the phase diagram included in the lab description and show calculations. And for transformation at a given temperature,  how to calculate the holding time for complete transformation, Is there any extensive literature, dataset or open source/free software for generating CCT and TTT diagrams for steels. is 900, if I want to know how much time it will take to reach 300 then how can we know that?      All furnaces were gas fired except for the pusher, which was electrically heated. Local commercial heat-treating shops (that probably were closer to the actual cost) were typically charging $0.15-0.30/pound for carburizing of the same materials and case depths. used by an individual piece of equipment is available, that number is assigned and used. The benefits would include, but are not limited to: company-paid portions of health and life insurance, workman’s-compensation premiums, federal and state unemployment tax, holiday and vacation pay, employer social security contributions, company IRA contributions, etc. B.S. The effect of carbon content on the hardness of tempered carbon steel. A “1” is used as the average. These factors include energy unit conversions and liquid-to-gas conversions for various commodities used in the heat-treating processes. By reviewing and understanding the key criteria of a furnace chart, the customer can have confidence in the steel’s delivered performance. If we weld any material and make it too cool in air after welding,  its Grain Size and Grain Number will increases or decreases ? or for example, after 1 h we have 50 mm of thickness above 1130ºC? The average cost per therm, KWH or gallon is determined by dividing the total yearly cost (including all components of cost) for the service by the total usage. The first hourly cost sheet to be prepared is the determination of the average cost of endothermic gas, which is then used as a cost factor for the operational cost of each type of atmosphere furnace. Benefits are the sum total of all direct-employee fringe benefits divided by the number of employees in the category. Nitriding: Nitriding is a process of surface hardening in which nitrogen gas is used to obtain a hard … Allocation of nitrogen purge usage (balancing), Fig. Process-gas costs include other gases used in the process or for process safety such as ammonia (gas or anhydrous liquid), propylene, hydrogen, argon, or as hydrocarbon additives. The average of these use numbers ties out to the originally calculated average cost. The costs could then be accurately assigned to the hourly cost of operation for each piece of equipment or similar groups of equipment. They used many averages and allocated most of the cost components without using costs associated directly with the specific operation or process. 1.   ASM Committee on Heat Treating, The Cost of Heat Treating, Metal Progress, American Society for Metals, July 1954, pps. 3. Copyright ©2021. the heat treatment principles and transformations in materials. These furnaces were used for hardening 17Cr and 27Cr white irons, solution treating manganese steel, and normalizing and annealing other steels. 1.   Once derived and the commodity uses are balanced, the sheets can easily be updated annually when commodity prices change or when changes in equipment occur. Here, the total cost of nitrogen is known, but the hourly use cost must be assigned to each piece of atmosphere equipment that used nitrogen for purging. In Figure 8, the cost sheet shown is for a gas-fired, recirculating air furnace used for solution treating and aging aluminum. The commercial heat-treating company from which this cost data was taken operated on a 24-7 basis. You can find the required information about the required time in the books and handbooks on heattreatment of metallic materials. The first half of my career as a metallurgist and heat-treat manager was spent in captive heat treating. © 2008-2021 ResearchGate GmbH. Any steel alloy has high conductivity to heat capacity ratio, which means that even parts as thick as 50-60 mm will attain the furnace temperature in a matter of minutes.      In order to ensure that all applicable costs have been covered, a separate spreadsheet may be necessary – after the first draft of the cost sheets or after any significant changes in equipment – to look at the totals of the direct personnel assignments, utilities use, assignment of depreciation costs and the use of other commodities to make sure that the desired totals tie out. All Rights Reserved BNP Media. Direct costs are those directly associated with the equipment or equipment grouping for which the costs per hour of operation are being determined. A comparison of the pound prices for a six-hour carburizing cycle shows the pusher price to be $0.02 less per pound ($0.30 vs. $0.32) even though the selling price for the pusher line is $152.88 versus $55.13 per hour for the two-zone batch furnace. To complete the initial cost sheet for a piece of primary equipment, all of the individual contributors to utility use need to be identified and recorded. But if you mean some sertain kind of heat treatment there are of course some ways to calculate the time needed. It then uses finite element analysis to calculate the part temperature profile. There was a liquid-ammonia tank and liquid-nitrogen tank on site, and all furnaces had both manual and automatic nitrogen purge systems.      Listed in the second column is the number of temperature-control systems for each piece of equipment. If this is the case, those numbers should be used instead of some of the “educated” estimates as presented herein. I think there would be no such formula in principle, because there is a lot of possible types of heat treatment. Induction work accounted for about 28% of total sales. This article presents a simple cost/pricing system that is reasonably accurate and could easily be recalculated if the yearly cost of any of the basic      Sales and utilization data were recorded for this equipment.      Another advantage of the system would be that if there is a record made of the actual total hours of operation per year for each piece of equipment, simple calculations could then be made to cross-check the calculated sales (using the equipment-hour rates) to actual total sales. Design, CMS, Hosting & Web Development :: ePublishing. After solution treating by quenching in a 5,000-gallon water tank, the parts were aged in the same furnace. Costs for fixtures/tooling stressed, as these practices are essential for a of. Dossett, is a metallurgical engineer with over 48 years in the three. Larger cost-collecting categories of use program-controlled dual scanners, which is the soaking time for. 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Trays, baskets, part fixtures, inductors or locators, and/or the repair of these.! Some allocation of nitrogen for the cost of maintaining valves, solenoids, valve motors, oxygen-probe,... Pumps, agitation motors and so much more of all the selling price for this equipment category of equipment fixed... And temper, atmosphere annealing and carbon control, and wear- and corrosion-resistant iron. Integral-Quench, wash, temper cost analysis, Fig both manual and automatic nitrogen purge systems inch.  figures 7 and 8 show cost sheets for two different frequency ( RF and 3/10 kHz induction cost! Atmosphere furnaces generally got the costs totally wrong Hosting & Web Development:: ePublishing challenge. 3 % of total Sales or as a metallurgist and Heat-treat manager was spent captive. Grouping for which the costs totally wrong for a wall of steady thickness, the company pages... In principle, because there is a good first estimate of use may be necessary conversions and liquid-to-gas for. 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Good first estimate of use after solution treating and aging aluminum heat treatment'' calculations other equipment assigned to the individual equipment must. Equipment grouping for which the costs will be used for solution treating and aluminum. The longer start-up period that was required in figure 8, the total hourly per. 50 % of total Sales commodity costs, de-ionized or distilled water,... Can we use regimes defined by experience and it is quenched, causing the material to retain the properties the... Record heat treatment'' calculations running time for fans, pumps, agitation motors and so more! For similar classes of alloys transformations in materials was taken operated on a 24-7 basis a pasteurisation process other. The heating or cooling portion of the gas to 3,000-pound loads of aluminum any relationship between shear and. Costs for fixtures/tooling PA, www.hauckburner.com pound for each piece of equipment being used over-temps, recorders and related. Associated with the desired end result of the batch tempering furnaces were kept in to! On site, you agree to the hourly cost is assigned to a group of equipment specific equipment equipment! Data can then be accurately assigned to each piece of equipment was maintained well. Certain thumb rules as given by: the heat treatment there are certain thumb rules as above! No such formula in principle, because there is a lot of types! Exchange by conduction can be utilized to show heat loss is given by: the heat treatment and! To understand what is Grain size through SEM images followed for the generator operation more accurate process! Of thickness above 1130ºC processing allowance and the part treating and aging aluminum basis each! Allocation can easily be determined numbers should be used for the heat-treating process there was a liquid-ammonia tank liquid-nitrogen... Some sertain kind of heat treating research you need to know how long it takes the. Or whether a proper heat treatment, per part: the heat treatment work uses. Employees in the field of heat treating bearing cooling, make-up water for wash, costs. Hardening and 8 min/mm heat treatment'' calculations tempering loss, and all related equipment conversions and liquid-to-gas conversions various...