Patent ID: 11946856
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A steel fracture starting point estimation method for estimating a fracture starting point of steel, the method causing a computer to execute:
a first step of calculating a hydrogen concentration distribution in steel-to-be-estimated when the steel fractures due to hydrogen embrittlement;
a second step of calculating critical hydrogen content at which the steel-to-be-estimated fractures due to hydrogen embrittlement; and
a third step of reading the hydrogen concentration distribution out of a storage unit, calculating, from the hydrogen concentration distribution, a location in the steel in which hydrogen concentration of the critical hydrogen content is distributed, and designating the location in the steel as the fracture starting point of the steel-to-be-estimated,
wherein the first step includes calculating a hydrogen diffusion coefficient of the steel-to-be-estimated based on variation of hydrogen content in the steel with time on assumption that hydrogen diffuses in the steel, and calculating the hydrogen concentration distribution based on the following diffusion equation:, C
      
       C
       s
      
     
     =
     
      
       4
       a
      
      ⁢
      
       
        (
        
         
          D
          ⁢
          t
         
         π
        
        )
       
       
        1
        2
       
      
     
    
   
   
    
     (
     1
     )
    
   
  
 

where C is a hydrogen content in the steel-to-be-estimated, Cs is a saturated hydrogen content, α is a radius of the steel-to-be-estimated, D is the hydrogen diffusion coefficient, and t is a hydrogen charging tie.