Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_15 ( solidat__ INTEGER, purpose VARCHAR, hardness___brinell__ VARCHAR )

### Question ###
What is the sum of Solidat (c) that's purpose is display type, heavy duty jobs, and a hardness (brinell) is smaller than 33?

### Accurate SQL ###

SELECT SUM(solidat__) AS °c_ FROM table_name_15 WHERE purpose = "display type, heavy duty jobs" AND hardness___brinell__ < 33