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#1169 - 09/21/15 12:47 AM Steel Shots Breakdown rate
Subhajyoti Offline
Member

Registered: 09/18/15
Posts: 7
Loc: India
Hello,

Shot Peeening Process details:
3000rpm shot impeller, 2seconds peening time per part, 1second indexing time, S230 @46HRc, Part at 46HRc, Part shape is 3mm thick & 200 dia stamped disc mounted horizontally (shots flowing from top) a 20mm annular central hole in the part, One part after another gets shot peened.

Question:
Using the above inputs, what is maximum expected breakdown weight% per hour for the S230 steel shots from nominal 0.6mm sieve(size) to 0.3mm sieve(size).


I need a opinion from the expert about this.

An early reply would be immensely helpful.

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#1171 - 09/21/15 07:39 AM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Socrates Offline


Registered: 02/20/06
Posts: 107
Even with the detail provided a maximum breakdown rate cannot be predicted. All things are relative. SAE J445 specifies durability tests that should be carried out by your shot supplier. If you retain a acceptance sample (about 100 g)of your incoming shot then durability can be re-checked.

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#1172 - 09/22/15 03:20 AM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Subhajyoti Offline
Member

Registered: 09/18/15
Posts: 7
Loc: India
Immense thanks for the prompt & specific reply. I will follow these lines.

Further,
Any "Good Amps" guide for Shot Peening?

What can be a "good amps" range for Shot Peening round Steel Plates (3mmthick) at 46HRc with S230 Shots also at 46HRc?

What can be called as higher & Lower limits of Amps for useful Shot Peening with the above process parameters.

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#1173 - 09/22/15 07:19 AM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Socrates Offline


Registered: 02/20/06
Posts: 107
I am not sure what you mean by "good amps". Reputable wheel blast machine manufacturers normally provide good advice as to the relationships between power,(e.g.HP),RPM and shot velocity.
As shot feed increases so does the power needed to maintain a required shot velocity. Increased shot flow at a given RPM also reduces the induced peening intensity. Useful charts are available on The Shot Peener web site.

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#1174 - 09/22/15 11:55 PM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Subhajyoti Offline
Member

Registered: 09/18/15
Posts: 7
Loc: India
Thanks again for the prompt response.
I'll lookup the details.

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#1175 - 09/23/15 11:32 PM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Subhajyoti Offline
Member

Registered: 09/18/15
Posts: 7
Loc: India
I searched the Library & got a few useful details.

Could you give links (titles) of some of the articles (in the Library) which substantiate the above statements:
"a)As shot feed increases so does the power needed to maintain a required shot velocity.
b)Increased shot flow at a given RPM also reduces the induced peening intensity".

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#1176 - 09/24/15 07:47 AM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Socrates Offline


Registered: 02/20/06
Posts: 107
(a) On the Shot Peener web site go to "Learning", then "Charts/Graphs/Tools, then "Wheel Peening Applications", then "Chart for wheel speed, RPM, shot flow rate".

(b)the effect of shot flow rate on peening intensity is well-established. I cannot, however, recall a specific chart reference.

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#1177 - 09/24/15 11:48 PM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Subhajyoti Offline
Member

Registered: 09/18/15
Posts: 7
Loc: India
With your hints above, I found some new ones as well. Thanks.
What does A2 Intensity mean? Is it meaning checking by using A2 spec Almen? Then what does it mean when we say A Almen- are we refering to A1 or A2 or ..... which one?
Also the graph in presentation "Shot size & speed to achieve Almen Intensity" under say same link as in your response above, looks a bit confusing to me. A, C, N are shown side by side bunches of graphs (which graph for which I cannot understand) & abscissa says A2 Almen. Can you please explain the various aspects of the graph in brief so that I do not make any wrong interpretation out of it.
Also, in presentation "Chart for wheel speed, RPM, shot flow rate", "# min" is what unit? What about the blanks in the table? Are they "data not available" or are they "not applicable cases"?

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#1178 - 09/25/15 01:34 PM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Socrates Offline


Registered: 02/20/06
Posts: 107
A1 and A2 are two grades of Almen strip - sometimes referred to as "aero grade" and "auto grade " respectively. Derived Almen intensity is independent of strip grade - but more data scatter occurs with lower grade Almen strips.

SAE J443 clearly states the limits of intensity for which different thicknesses are suitable. At high intensities C strips should be used - at low intensities N strips should be used. The graph markings show the approximate limits for N, A and C strips with A strip values used for clarity of presentation.

I do not know what # min means but it could easily be lbs per minute. Manufacturers are loth to publish information that could be used against them! The greater the HP the more expensive will be the installation. That is why there are limits - equivalent to your "not applicable cases".

Must end this thread now. For more extensive training why not go to an EI Workshop?

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#1179 - 09/28/15 02:25 AM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Subhajyoti Offline
Member

Registered: 09/18/15
Posts: 7
Loc: India
I think you have been lot patient to clarify my basic doubts. Thanks. I also think we can end this thread here.

How are the details of EI training? Our Company is situated in India. Can our team benefit from this training sitting here or what is the way? Could I get some details of it? My mail ID is sensbh@schaeffler.com.

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#1180 - 09/28/15 06:57 AM Re: Steel Shots Breakdown rate [Re: Subhajyoti]
Dave Barkley Offline


Registered: 04/13/11
Posts: 43
Loc: USA
The closest EI SPT Seminar to India is in Singapore. You can find more details here: http://www.shotpeeningtraining.com/seminars/singapore/
_________________________
Dave Barkley
EI Shot Peening Training

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