Insert b tag when pressing b button instead of strong tag

Is it possibile to modify the TinyMCE editor in such a way that:

• clicking the b (Bold) button would generate a <b> tag, rather than a <strong> tag
• clicking the i (italic) button would generate a <i> tag, rather than a <em> tag

I tried placing this code inside functions.php but it didn’t work

add_filter('tiny_mce_before_init', 'modify_formats');

function modify_formats($settings){
   $formats = array(
     'bold' => array('inline' => 'b'),
     'italic' => array('inline' => 'i')
    );
    $settings['formats'] = json_encode( $formats );
    return $settings;
}