How to connect a roller-bit steel report to the right component

DRILLNOVA · Technical guide · Updated

A useful material file links the steel grade to the cone or leg, then to treatment and finished-part records. The component identity comes before the test numbers.

01

Keep cone and leg material records separate

In this MH-3 manufacturing example, the cone record identifies 15MnNi4MoA and the leg record identifies 15CrNiMoA. Preserve the full grade suffix and the specification reference.

These are records for different raw-material samples. One is not a substitute for the other.

Legs after preliminary machining. The leg material record belongs to this component type, not to the cone.
Legs after preliminary machining. The leg material record belongs to this component type, not to the cone. Tap image to enlarge.

The cone and leg need different record links

MH-3 example: material identity is tied to the component
ComponentRecorded materialNext record to connect
Cone15MnNi4Mo; attached raw-material report uses 15MnNi4MoACone batch → heat-treatment condition → insert pockets and finished bearing bore.
Leg15CrNiMo; attached raw-material report uses 15CrNiMoALeg batch → journal hardfacing and treatment → finished journal dimensions.

Keep the suffix printed on the selected material report. A report for the leg does not identify the cone, even when the two parts arrive in one assembled roller bit. These grades belong to this MH-3 example. Match each supplied component to the selected drawing and batch documents.

02

Identify the condition in which a part was tested

Raw-steel properties, heat-treatment checks and finished-journal inspection answer different questions. Keep the sample identity, method and treatment batch with each result.

A hardness value for supplied steel is not automatically the acceptance value for a finished bearing surface.

Heat-treatment stage in the MH-3 process example. Keep the treatment batch linked to the component record.
Heat-treatment stage in the MH-3 process example. Keep the treatment batch linked to the component record. Tap image to enlarge.

A hardness value needs a location and a process stage

Read these fields together
FieldWhy it changes the interpretation
Material chemistry and heat identityIdentifies the steel; it does not demonstrate the finished bearing-surface condition.
Heat-treatment batch and sequenceConnects the component with the treatment actually applied.
Hardness scale, load and test locationA surface result and a core result describe different locations; HRC and HV are not interchangeable labels.
Case-depth requirement and method, where specifiedChecks how the hardened layer develops below the surface, rather than repeating only a surface reading.
Machining stage of the measurementState whether the result is before or after final machining, and use the inspection location specified for that stage.

Carburising raises carbon at the surface so that subsequent heat treatment produces a wear-resistant layer. That is why chemistry, hardness location and treatment condition belong together. A furnace temperature alone is not a finished-part acceptance result. Technical background: TWI on carburising.

03

Follow the identity through to the finished assembly

Connect material batch → cone or leg → treatment batch → finished assembly. Ask for this record chain in the order specification and check it at receipt.

A missing link can leave a valid steel report unconnected to the parts delivered.