Advantages of using Castings over a Bar-stock, for Hot-chamber Plunging-system components. [Metallurgical-perspective]

[madhav kapdi]

                Sub. : Advantages of using Castings over a Bar-stock, for Hot-chamber Plunging-system components. [Metallurgical-perspective]

 

                Background. :  

                Now a days, virtually 100% of the Die-casters are using the readily available Bar-stock [Extruded] from the market for the manufacturing of individual components, but i would like to bring to your notice, the disadvantages associated with the Bar-stock, as under,

 

                01] Dis-advantages associated with the Bar-stock.

 

                01] The Bar-stocks available in the market are expected to be an extruded product and the raw material used for the Extrusion is expected to be Electro-slag Refined [ESR] make ingots. Merely the ESR make ingots is not a guarantee for the product quality, but it depends upon the quality of Refining slag [CaF2 based] and also the input raw material, decides the Quality of the extruded product [Bar-stock]

 

                02] If the raw material input is not an ESR make, then the Quality of the product is not assured / guaranteed and the Die-casters should stay away from such Bar-stock.

 

                03] Even if you take the lowest size of the extruded bar of say 50 MM Dia., then the original ESR bar for that should be of 150 MM Dia. minimum since anything less than that will not be commercially viable, for the power Guzzling ESR operations,

 

                04] Obviously the 150 MM Dia. bar will have to undergo multiple stages of reduction [Extrusion] to reach the final size of 50 MM Dia.

 

                05] Every Extrusion operation will call for the Re-Heating & Extrusion, which will reset the Re-crystallization temp. every now and then, which the Extruder has to take into consideration, before the subsequent operation, to avoid the Grain-growth.

 

                06] Repeated Heating & Extrusion, will induce the Work Hardening related stresses into the Bar-stock, to which you will further add your own machining  [Stock removal] related stresses, which at times is more than 50% of the original weight [Raw material] Plz check the difference, due to the stock removal, in case of the Piston-rings, subjected to the highest abrasive wear.

 

                07] Extruded products don't have an Isotropic properties [same properties in all the Directions] in view of the elongated Grain-structure, which calls for the intermediate Heat-treatment called Patenting for the Equi-axed Grain structure,

 

                08] Repeated Heating [in case of Bar-stock] increases the Carbon print. We should make every attempt to reduce our Carbon footprint.

 

                02] Advantages associated with Casting.

 

                01] The individual casting will reduce the section from 150 MM to say 25/30 MM or even less, obviously then the Grain-size will also reduce considerably, which should increase the strength and also the life of the components.

 

                02] Due to the reduction in the section, there will be reduction in the Primary-Carbide particle size and also the Secondary-Carbides particle size after the Heat-treatment, which is bound to supplement the strength of components.

 

                03] Absence of the repeated Heating for the Extrusion and also the Patenting will reduce the Carbon print considerably.

 

                04] In my opinion, the practice of using the Bar-stock over the casting, is a self induced indiscipline [Short-cut] by the Die-casters, and they themselves have to undertake the course correction, and insist for the castings, as a raw material, from the vendor for the components, to improve their own Tooling performance.

 

                03] Dis-advantages associated with the castings.

 

                01] Low casting weight calls for the Shell moulding process, which calls for the expensive Pattern cost, while conventional sand castings have their own problems.

 

                02]  Shell moulding calls for the bulk requirement also hence the Die-casters have to consolidate their vendor base to generate the Economic Order Quantity [EOQ] a precondition for the sustainable business activity.

 

                03] The standardisation does not exist with the Diecasting Industry, This is a must to generate the EOQ.

 

                04] The reduction in thickness will reduce the Primary Carbide particle [PCP] size. The reduction in PCP size is also associated with the increase in the strength and also the performance

 

                05] Reduction in the Grain size will also reduce the size of the Secondary-Carbides particles [SCP] after the Heat-treatment. The reduction in SCP size will increase the strength of the component, and also the performance.

 

                06] Improvement in the performance of the components as mentioned in the point number 04 & 05, will reduce the consumption of the components. The reduction in the consumption will affect the business of the vendor using the Castings as the raw-material. If the business of the vendor is found going down on account of the improved component performance, then his backing out from the business is not ruled out.

 

                What is the option then.?   

 

                07] You have to pay the Performance Linked Prices [PLP] for the components, for the vendor to remain interested, otherwise this Development will die its natural death in absence of the  professional patronage.

 

                Bottom lines. :  

 

                01] Die-casters have to take the proactive steps, and insiste on the Castings as a raw material for the component manufacturing.

 

                02] Die-casters have to pay the Performance Linked Prices [PLP] for the sustainable business activity.

                Madhav kapdi.
                [9860081951]