не могу понять о чем говорится в части "because we normally bought the complete Heat Charges to the foundries asking for the most restrictive Chemical Analysis"

Это письмо от производителя, в котором производитель объясняет почему для некоторых деталей указан определенный хим.состав.

Контекст:
These UOP Classes depend on the dangerous of the service, as an example HF-1 Class is for valves in Hot & Wet Hydrofluoric Acid Service and these valves are normally constructed of Full Monel.
On the other hand, the HF-2 Class is for valves in HF Acid Service and the valves used here are in Carbon Steel with all the Internals in Monel and also accessories like Grease Injectors, Teflon inserts among others, besides the Chemical Restriction on the Carbon Steel.
Other classes like HF-4 or HF-5 are for services that only has traces of HF acid service and the valves requested are in Carbon Steel with Monel internals, but without accessories and no chemical restrictions.
In our case, doesn’t mean that our valves will have different chemical composition, because we normally bought the complete Heat Charges to the foundries asking for the most restrictive Chemical Analysis, no matter for which UOP Class is the valve intended, but if the spec doesn’t call for the restriction, is not a must to comply with it.

Заранее спасибо!