Section 1 Materials of Chemical Equipments Section 2 Des.ppt

Basic of Chemical Machinery Equipments Section 1 Materials of Chemical Equipments Section 2 Design of Chemical Vessels Section 3 Mechanical Design of Typical Equipments Reference: Structural Analysis and Design of Process Equipment Section 1 Materials of Chemical Equipments 1.1 Summarization Definition: The capability of materials to resist external forces, but does not deformation beyond allowance or wreck. Elastic State(curve ob) portional limit: Strength: i. Yielding State (near point c) For the metal materials which have no apparent yielding phenomena,it’s stipulated that: σ0.2 = stress in 0.2% of residue elongation *The stress of any point in the pressure vessel caused by pressure from medium should be below the elastic limit and cannot happen the plastic deformation. ii. Elevated temperature: 3) Creep Limit σn #Creep limit σn (MPa): Definition: 持久强度 under certain temperature, the material cracks in a stress after a period of stipulated time. This stress is called creep rupture strength. Stipulated time: 105 hours Because the designed life time of chemical equipments is commonly 105 hours, the stress under which material cracks is said to be rupture strength. 5) 疲劳极限(Strength) σ-1(MPa) 塑性 The meaning of Percentage Elongation: i) The value of ? reflects the degree of the plastic deformation before the material cracks. ii) The larger ?, the better the plasticity of material. iii) Plastic material ? 5%; Low carbon steel ? = 20~30% iv) Hard brittle material ? 5%; Cast iron ? = 1% 断面收缩率（?） After the unit of structure is cracked, the ratio of the reduced area of the cross-section and the original (cross) sectional area is called Shrinkage of Sectional Area which is described by ψ%. Cold Bending Property 硬度 The test of HB: The relationship of Hardness and Strength: Gen