Casting info--Car transmission housing

September 02, 2024

1.Casting info

name: Car transmission housing

requirements: pressure tightness

casting process:

Die Casting machine tonnage:3500T

punch dia(mm):170

material: ADC12

casting weight (g):12718

filling weight(g):15917

casting size(mm):258*400*500

average wall thickness(mm):5.44

high speed m/s:4.8

dry injection stroke(mm):1030

high speed switching position (mm):760

flow gate section mm²:3800

2.Casting question

there are air holes on the joint face of the valve plate,the oil duct hole leaks

3.Casting picture

4. casting analysis

1. Close to the section C21-C21（valve plate joint face),porosity is exposed after machining.after analysis,the porosity is caused by runner face to the thread hole boss,then it rebo2.on section A10-A10(oil duct 6#),high pressure cooling of oil duct core failed(blocked by regular tap water’s scale)and far way from the gate, pressure can not be replenished,all these lead to shrinkage porosity. this shrinkage porosity is through to the beside thread hole,leak.

3.on section C15-C15(4# oil duct),this shrinkage porosity is caused by extrusion depth is not enough and ineffective extrusion.this shrinkage porosity is through to the beside thread hole,leak

4.Through comprehensive analysis of the process parameter,shrinkage porosity is also related to punch resistance,pressure and velocity loss.（see picture 5）

5.improving measures

1. adjust and optimize the flow gate, block 6mm flow gate the which direct to thread hole boss(the porosity generated position).

2.add aided runner,and optimize the cooling water way of 6# oil duct core

3.increase the extrusion depth.and optimize the factors that impact extrusion.

4.For issue of high pressure point cooling invalid,add a water softener,so there is no scale formated in the mould cooling water runners.

6.improving results

1.near section C21-C21(valve plate joint surface ),after processing,no porosity, pass rate 100%

2.on section A10-A10(oil duct 6#),airtight pass rate 93%

3.on section C315-C15(oil duct 4#) ,airtight pass rate 91%

4.One-time airtight pass rate is 92%,balance 6% is a little leak between 3.5-8ml/min,which all pass after infiltration .2% big leak is scraped,Synthetical pass rate is 98%

7.tips

For stability of extrusion:

extrusion effect is related to the internal pressure in metal liquid when extrude.and this pressure is fluctuated along with the factors such as slug thickness,mould temperature,metal temperature, equipment pressure and etc.

ladling machine precision also affect extrusion signal‘s accuracy.

Author:

Mr. Logan

E-mail:

sales3@bldiecasting.com

Phone/WhatsApp:

8618157495020