X1000!!!dfree383 wrote:
1) Factory SBC blocks suck reguardless of the metal.
2) The stock stuff is a waste of time for racing (Thank you Dart, World, Bowtie and Others)
And add in factory SBF for number 1 too
Moderator: Team
X1000!!!dfree383 wrote:
1) Factory SBC blocks suck reguardless of the metal.
2) The stock stuff is a waste of time for racing (Thank you Dart, World, Bowtie and Others)
The metallurgy of the material can certainly be a factor in the machinability of the block, so I can appreciate your cynicism regarding the heat treating of castings within the mold. However, I think you might be using the term "hardness" when you mean "toughness". Toughness is the ability of a metal to absorb energy. Hardness is the ability of a metal to withstand wear. Nickel improves the toughness of the casting, and helps to even out hardness throughout the casting. Having said that, I can take the toughest cast iron alloy you'd like to use, and make the brinell low enough that it will wear in half of the time required to wear the equivalent casting with a brinell that tests at the ASTM or SAE specification of the same alloy. So, one could say that both hardness and toughness will determine the machinability of the block. The heat treating of the casting while still in the mold will largely determine the hardness of the casting.dfree383 wrote:
Oh yea almost forgot....... The machining hardness differences in the stock blocks are because of cooling time of the castings not the metal itself..
The US has under 20% of the world's installed wind generation capability and we generate 27% of the world's wind based electricity. No other country is generating as efficiently as we do, and only China has a larger installed base. And at the rate we're putting generators up, that's going to change in the near future as well.kirkwoodken wrote:True, some adjustments need to be made, BUT Germany is still doing it the "old way", but doing it more efficiently. 50% of German electric is now being produced by wind. French electric is being produced with fissionable materials being reclaimed from Russian nuclear bombs. We could be doing the same.
The ductile iron inoculating ladles should be stepped at the bottom so that the Mg can be put in the lower bottom so the molten cast iron can "pour" over it so that the nodularization(Sp?) process takes place.Mod77L wrote:I have always just lurked here, sponging info from all the rest of you, so this is my first post. I work for a foundry that casts ductile iron, so I finally have something intelligent to add.
The hardness of the iron can be controlled by the amount of carbides formed during cooling. Faster cooling = more carbides = harder, but more brittle iron. If you cool it too fast, you can get white iron. Tin or copper can be added to help regain the yield and tensile strength lost. The difference between grey iron and ductile (nodular) iron is the addition of magnesium. Magnesium is what creates round graphite nodules instead of flakes (grey iron). The round nodules are what gives ductile iron it's superior strength. Porosity is controlled through the gating and risering system. Most castings contain some amount of porosity. The trick is to keep it out of machined and/or safety-critical areas.
There should be no difference in alloy content between parting line and thick section material. The parting line flash may contain a slightly higher level of carbides, but since that area is usually ground off, and superficial only, it's metallurgy is not important to the casting as a whole.
Those are the basics, if you want to get down to what % of what alloy does what, that is what the guys in the lab are for, lol.
I have a similar experience.GLHS60 wrote:
Around 1972 I was working in an automotive machine shop assembling Engines and the machinists often commented the 1968 and newer model year SBCs were "softer".
Especially the cylinder head guys who reamed the valve guides for what I think were 5000 series liners.
Anecdotal for sure but agrees with what you reported.
Thanks
Randy