Subject: How does steel purity affect the fatigue life of a bearing?

In an ongoing attempt to find competitively priced bearings we are doing 
global searches for common bearings.  To be sure that the same number 
bearing from one supplier is an identical bearing from another 
manufacturer, the manufacturing equipment and tolerances may all be the 
same but the steel supplier significantly impacts the rating.  One 
supplier has already proved that product that he makes in a second to 
third world country, using the same machinery, is not the same.  The only 
difference that they were able to identify was the purity of the steel 
that was used to make this "identical" bearing.  Since large bearing 
companies have plants in a variety of countries, using different sources 
for their raw material, how can I be sure that a bearing that is made in 
one country is the same that might be made in the U.S. or Japan?  Is there 
any way to quantify this by steel purity?

Re: How does steel purity affect the fatigue life of a bearing?