An iron-carbon alloy initially containing 0.258 wt% C is exposed to an oxygen-rich and virtually carbon-free atmosphere at 1120°C. Under these circumstances the carbon diffuses from the alloy and reacts at the surface with the oxygen in the atmosphere; that is, the carbon concentration at the surface position is maintained essentially at 0.0 wt% C. At what position will the carbon concentration be 0.194 wt% after a 6 h treatment? The value of D at 1120°C is 6.9 × 10-11 m2/s.

1.95 mm

Explanation:

Let's calculate the carbon conc. 0.194 wt% after a 6 h treatment using the expression:

From the erf z table, at erf(z) = 0.752

z = 0.80

Thus,

Where d =

Time, t = 6 hrs = (6 * 60mins * 60secs)

Substituting values:

Solve for x:

x = 1.95 mm

The position will the carbon concentration be 0.194 wt% after a 6 h treatment is at 1.95 mm

unlike the threaded fasteners which are used to clamp the machine members, power screws are used to transmit power. common applications of power screws are: screw jacks: to lift weight. lead screw of lathe: for axial movement of tool and its precise positioning.

answer: report them

explanation: