Friday, May 4, 2012

030070010 Celal Selçuk Tiftik Bonus words

Warm Forging


In cold forging of parts with relatively com-plex geometries from high-carbon and alloysteels, forging pressures are extremely high andthe ductility of the material is low. As a result,short tool life and defects formed during forginglimit the economic use of the cold forging processes. Consequently, in manycases,warmforging, i.e., forging at temperatures below recrystallization temperature, is commonly used[Altan et al., 1983]. For warm forging, steels areusually heated between room temperature andusual hot forging temperature. The normal temperature range is considered to be 1110 to 1650 F (600 to 900 C). An exception is the warmforging of austentic stainless steels, which usually are forged between 390 and 570 F (200 and300 C) [ICFG, 2001b]. The process may be in-terpreted broadly as thermomechanical process-ing at elevated temperature to achieve the fol-lowing advantages:


●A reduction in flow stress. This isapplicable,in particular, to high-alloy steels. As a result,tool stresses and forging loads are reduced(Fig. 17.26).
●Greater ductility of the forged part. This al-lows more complex shapes to be forged.
●A reduction in strain hardening. This mayreduce the number of forming and annealingoperations.
●Greater toughness of the forged part
●Improved accuracy as compared to hot forg-ing
●Enhanced product properties through grainrefinement and controlled phase transfor-mations in heat treatable steelsAs an example, variations of tensilestressandductility (as indicated by reduction of area) withtemperature are shown in Fig. 17.26 for 1045steel. It can be seen that the tensile stress doesnot decrease continuously with temperature.There is a temperature range, in this case, at ap-proximately 400 to 800 F (205 to 425C),wherein forging would not be recommended.Warm forging requires determination of the op-timum forging temperature and the suitable lubricant. Selection ofwarmforginglubricantshasproved to be especially difficult. The factor thatlimits the use of warm forging is that the technology is still undergoing development, particularly in aspects of surface treatment,lubrication,and tooling.Tooling for warm forging is similar to that forcold forging, with some modifications made inthe die to allow increased temperatures, internaldie cooling, and venting of coolants.



(Cold And Hot Forging: Fundamentals And Applications  ,Taylan Altan,Gracious Ngaile,Gangshu Shen p.233)


***There is no old definition...


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Continuous transfer


       In this continuous method of transfer line , the work pieces are moved continuously at constant speed.This requires the work heads to move during processing in order to maintain continuous registration  with the work part.
    For same types of operations this movement of the work heads during processing  isn’t feasible.It would be difficult ,for example , to use this type of system on a machining transfer line because of inertia problems due to the size and the weights of the work heads .In other cases , continuous transfer would be very practical . Example of its use are : Packaging , beverage bottilng operation , Manual assembly operations  and simple assembly  tasks.
       Continuous transfer systems are relatively esay to design  and fabricate and also can achive a high rate of production. 

(Computer Integrated Manufacturing  , M.S. Ganesha Prasad,B.S. Raju , p.19)


***There is no old definition...


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Utilization and Availability


    To construct a disparity ratio, we must define each of its components of utilization and availability. First, however, we must define a WOSB. he SBA definition of a small business, for 
federal contracting purposes, varies by industry. In manufacturing, mining, and wholesale 
trade, the definition is based on the number of employees. Firms with fewer than 500 employees are considered small in manufacturing, and firms with fewer than 100 employees are considered small in wholesale trade. Annual revenue is used to define small firms in many other 
industries, such as construction (less than $28.5 million), retail trade (less than $6 million) 
and service firms (less than $6 million). he subset of small businesses that are women-owned 
comprises those of which at least 51 percent is owned by women. One can imagine scenarios 
in which the number of women-owned or small firms is overstated because firms wish to present themselves that way in order to receive preferential treatment in SBA programs. One can 
also imagine that characteristics of firms can change over time without any intent to “game the 
system,” through firm contraction and expansion, ownership changes, mergers, and the like. 
his report does not address these errors of classification.
We vary our measures of utilization and availability to create four basic kinds of ratio. 
First, we derive disparity ratios based on the dollar value of awarded contracts. hese are shown 
as 1 and 3 in Table 2.1. Second, we use number of contracts awarded to measure utilization. 
hese are shown as 2 and 4 in the table. 
A key decision in the derivation of disparity ratios is determining how to estimate availability. he first (and broader) method estimates the share of WOSBs in the economy. he 
second estimates the share of WOSBs among the set of ready, willing, and able firms. Which 
method is appropriate depends on the mechanisms thought to be at work. Disparity ratios do 
not measure discrimination itself, they measure the difference between men and women in 
some dimension, in this case, in winning federal government contracts. he difference could 
be due to a number of reasons, only some of which are discriminatory. For example, women 
might be more interested than men in industries where the federal government does not spend 
a lot of money, or they may be less interested in working with the government. hese factors 
suggest that the second method—focusing on ready, willing, and able firms—might be the 
correct one to use. Discrimination in the awarding of contracts, however, might result from


women business owners being less likely to bid on contracts. his would not be detected if the 
pool of available firms consists only of firms that have demonstrated their interest by bidding 
on contracts. Again, the disparity ratio can only measure the difference; it cannot explain it. 
he SBA requested that RAND define the population of firms that are ready, willing, 
and able to perform federal contracts in two ways. he first is the population of all firms in the 
economy (disparity ratios 1 and 2 in Table 2.1). he second is the population of firms that have 
registered as potential bidders for federal contracts (ratios 3 and 4 in the table). hus, in this 
report, we compute disparity ratios four ways: by contract-dollars and number-of-contracts 
ratios in which the population of ready, willing, and able firms is essentially all firms, and by 
contract-dollars and number-of-contracts ratios in which the population of such firms is all 
firms that have registered as potential bidders for federal contracts. 


(The Utilization of Women-Owned Small Businesses in Federal Contracting

 ,Elaine Reardon,Nancy Nicosia,Nancy Y. Moore, p.4)


***There is no old definition...


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