Bearing materials — service domain of tin-base white metals (Babbitts) Tin-base white-metal (Babbitt) bearings are primarily selected for which operating regime considering load, pressure, and wear characteristics?

Introduction / Context:
White metals (Babbitts) are classic bearing linings used on shafts and journals. They offer excellent conformability, embeddability, and seizure resistance. Understanding their best-use window—especially relative to load and speed—is crucial for reliable bearing selection in machines and turbines.

Given Data / Assumptions:

• Tin-base Babbitt is a soft, low-friction alloy with hard intermetallics dispersed in a soft matrix.
• Hydrodynamic lubrication is assumed during normal operation.
• The question targets typical design guidance rather than extreme specialty variants.

Concept / Approach:
Tin-base Babbitts excel in low to moderate unit pressures and high surface speeds, where an oil film can be maintained. Their softness protects the shaft, accommodates misalignment, and embeds debris. However, they are not intended for sustained very high loads or shock; harder bronzes or tri-metal bearings are preferred in those regimes.

Step-by-Step Solution:
Identify characteristic: soft matrix + good conformability → tolerant of slight misalignment and contaminants.Map to operating envelope: best at light load/pressure with adequate lubrication.Exclude high-pressure, high-shock duty, where fatigue strength must be higher.Thus select “light load and pressure.”

Verification / Alternative check:
Design handbooks specify allowable PV (pressure * velocity) values; tin-base Babbitts show relatively low allowable pressure compared with bronzes but handle good speeds, aligning with the chosen option.

Why Other Options Are Wrong:
“High pressure and load” overstates capability; “elevated temperatures” risk softening; “large surface wear” suggests boundary/dry regime, the opposite of intended hydrodynamic use; “intermittent dry rubbing” is inappropriate for Babbitts.

Common Pitfalls:
Picking a bearing solely for low friction without checking allowable unit pressure and temperature limits.

Final Answer:
light load and pressure