Method for predicting degree of corrosion of weather-resistant steel

A method for maintaining and managing a steel structure, comprising the steps of:

• finding an actually measured first-year corrosion amount from an actual measurement result of a corrosion loss in any given period of an actual structure made of an atmospheric corrosion resistant steel or a corrosion loss in any given period of a vertical exposure member or a horizontal exposure member which is made of an atmospheric corrosion resistant steel and attached to an actual structure;
• calculating a corrosivity index Z by the following equation (Eq. 6) from extrinsic corrosion information including weather observation data, an amount of airborne salt, and an amount of sulfur oxide in a location where the actual structure is installed, and intrinsic corrosion information on components of the atmospheric corrosion resistant steel, with an electronic calculator;
• estimating a first-year corrosion amount of the atmospheric corrosion resistant steel from the corrosivity index Z with the electronic calculator;
• comparing the actually measured first-year corrosion amount and the estimated first-year corrosion amount with the electronic calculator;
• correcting the corrosivity index Z based on a result of the comparison with the electronic calculator;
• predicting a corrosion amount of the atmospheric corrosion resistant steel based on the corrected corrosivity index Z with the electronic calculator;
• and
• determining a maintenance management policy based on the predicted corrosion amount.
• 8 Z = α · TOW · exp ⁡ ( - κ · W ) · C + δ · S 1 + ϵ · C · S · exp ⁡ ( - E a R · T ) ( Eq . ⁢ 6 )
• (where TOW is an annual wetness time (h) in the planned location for use, W is an annual mean wind speed (m/sec.) in the planned location for use, C is an airborne salt amount (mdd) in the planned location for use, S is a sulfur oxide amount (mdd) in the planned location for use, Ea is activation energy (J/mol) of a corrosion reaction of the atmospheric corrosion resistant steel, R is a gas constant (J/K(K·mol)), and T is an annual mean temperature (K) in the planned location for use. Moreover, α is a constant determined by a comparison with an actual measured value, and κ, δ, and ε are constants respectively representing the degree of influence of each of factors which they are associated with.)

A method for providing information on an atmospheric corrosion resistant steel, comprising the steps of:

• a user accessing a server for calculating a predicted corrosion amount of an atmospheric corrosion resistant steel with environmental data including weather observation data, an amount of airborne salt, and an amount of sulfur oxide, and intrinsic corrosion information on components of the atmospheric corrosion resistant steel from a terminal device via an electric communication line;
• the user inputting environmental data including weather observation data, an amount of airborne salt, and an amount of sulfur oxide in a planned location for use where an atmospheric corrosion resistant steel is to be used from the terminal device to the server;
• the user permitting the server to recognize intrinsic corrosion information on components of one or more than one type of atmospheric corrosion resistant steel planned to be used from the terminal device;
• the server calculating a predicted corrosion amount of each of the atmospheric corrosion resistant steels based on the environmental data and the intrinsic corrosion information;
• the server transmitting the predicted corrosion amount to the terminal device via the electric communication line;
• and
• the terminal device outputting the predicted corrosion amount.

A business method for an atmospheric corrosion resistant steel, comprising the steps of:

• a user accessing a server for calculating a predicted corrosion amount of an atmospheric corrosion resistant steel with environmental data including weather observation data, an amount of airborne salt, and an amount of sulfur oxide, and intrinsic corrosion information on components of the atmospheric corrosion resistant steel from a terminal device via an electric communication line;
• the user inputting environmental data including weather observation data, an amount of airborne salt, and an amount of sulfur oxide in a planned location for use where an atmospheric corrosion resistant steel is to be used from the terminal device to the server;
• the user permitting the server to recognize intrinsic corrosion information on components of one or more than one atmospheric corrosion resistant steel planned to be used from the terminal device;
• the server calculating a predicted corrosion amount of each of the atmospheric corrosion resistant steels based on the environmental data and the intrinsic corrosion information;
• the server transmitting the predicted corrosion amount to the terminal device of the user via the electric communication line;
• the terminal device outputting the predicted corrosion amount;
• and
• determining a business counterpart based on at least one type of element selected from the group consisting of the presence or absence of history of access to the server and the frequency of access to the server.

A business method for an atmospheric corrosion resistant steel, comprising the steps of:

• a person in charge of business inputting extrinsic corrosion information including weather observation data, an amount of airborne salt, and an amount of sulfur oxide in a planned location for use where a customer plans to use an atmospheric corrosion resistant steel to an electronic calculator for calculating a predicted corrosion amount of an atmospheric corrosion resistant steel with extrinsic corrosion information including weather observation data, an amount of airborne salt, and an amount of sulfur oxide and intrinsic corrosion information on components of the atmospheric corrosion resistant steel;
• the person in charge of business permitting the electronic calculator to recognize intrinsic corrosion information on components of one or more than one type of atmospheric corrosion resistant steel which the customer plans to use;
• the electronic calculator calculating a predicted corrosion amount of each of the atmospheric corrosion resistant steels;
• and
• the person in charge of business presenting a result of the calculation by the electronic calculator to the customer.

A system for predicting a corrosion amount, comprising:

• an input means for inputting information;
• a computing means for calculating a predicted corrosion amount of an atmospheric corrosion resistant steel with extrinsic corrosion information including weather observation data, an amount of airborne salt, and an amount of sulfur oxide in a planned location for use where the atmospheric corrosion resistant steel is to be used, and intrinsic corrosion information on components of the atmospheric corrosion resistant steel which are inputted from the input means;
• and
• an output means for outputting a result of the calculation by the computing means.

A system for selecting a steel type, comprising:

• an input means for inputting information;
• a computing means for calculating a predicted corrosion amount of each of atmospheric corrosion resistant steels with extrinsic corrosion information including weather observation data, an amount of airborne salt, and an amount of sulfur oxide in a planned location for use where the atmospheric corrosion resistant steel is to be used, and intrinsic corrosion information on components of one or more than one type of atmospheric corrosion resistant steel planned to be used which are inputted from the input means;
• a comparing means for comparing the predicted corrosion amount and a design permissible corrosion amount in a design life period;
• and
• an output means for outputting a result of the comparison by the comparing means.

A system for maintaining and managing a steel structure, comprising:

• an input means for inputting information;
• and
• a computing means for respectively calculating actually measured first-year corrosion amounts of a vertical exposure member and a horizontal exposure member which are made of an atmospheric corrosion resistant steel based on actual measurement results of corrosion losses in any given period of the vertical exposure member and the horizontal exposure member made of the atmospheric corrosion resistant steel which are inputted from the input means,
• calculating a predicted corrosion amount of the atmospheric corrosion resistant steel with extrinsic information including weather observation data, an amount of airborne salt, and an amount of sulfur oxide in a planned location for use where the atmospheric corrosion resistant steel is to be used which are inputted from the input means, intrinsic corrosion information on components of the atmospheric corrosion resistant steel recognized via the input means, and the respective actually measured first-year corrosion amounts;
• and determining a maintenance management policy based on the predicted corrosion amount.