Clasp blank ZMK-585M4 made of alloy ZlSrPlM 750-80-90

ZMK-585M4 is the model designation of the clasp blank. The material is specified separately in the nomenclature line: ZlSrPlM 750-80-90, and the supply is covered by the TU for clasp blanks for jewelry items.

What this item is

The model index should not be automatically read as a fineness: the composition corresponds to a 750-fineness gold alloy. Before use, it is necessary to obtain a unified document where ZMK-585M4, the alloy grade, and the geometry refer to the same version.

Composition and documents

• Grade: ZlSrPlM 750-80-90
• Gold: 75.0–75.5% by mass
• Silver: 7.5–8.5% by mass
• Platinum: 8.5–9.5% by mass
• Copper: balance
• Supply document: TU 9641-824-05785324-2006

The grade belongs to the gold–silver–platinum–copper system. The designation fixes the alloy composition but does not specify dimensions, hardness, or condition of the specific blank. Platinum should not be interpreted as a coating: by nomenclature, it is an alloy component. For process calculations, the batch certificate and delivery condition data are required.

Applications and technological role

• preparation of the clasp unit of a chain or bracelet when mating dimensions match;
• assembly, adjustment, and finishing of the fastener according to the working drawing;
• replacement of a part in repair only after checking the model, material, mass, and attachment method;

What to agree before ordering

Request the drawing of model ZMK-585M4, mating dimensions, mass, completeness, clearances, tolerances, and surface condition. Clarify which parts are included in the blank, how attachment and subsequent finishing are performed, and whether heating is allowed. The commercial offer and certificate must simultaneously confirm the model, grade ZlSrPlM 750-80-90, TU, and batch number; the name alone is not sufficient.

Safety and handling

Do not mix chips and dust with other alloys: this is important for technology and accounting of precious metals. Perform machining and polishing with local exhaust ventilation, eye and hand protection. During soldering, consider heated parts and flux fumes; parameters are taken from the approved process card. Collect waste separately.